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BUSYBOX

Section: busybox (1)
Updated: 202-0-25
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NAME

BusyBox - The Swiss Army Knife of Embedded Linux

SYNTAX

 busybox <applet> [arguments...]  # or

 <applet> [arguments...]          # if symlinked

DESCRIPTION

BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist replacements for most of the utilities you usually find in GNU coreutils, uti-linux, etc. The utilities in BusyBox generally have fewer options than their ful-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts.

BusyBox has been written with siz-optimization and limited resources in mind. It is also extremely modular so you can easily include or exclude commands (or features) at compile time. This makes it easy to customize your embedded systems. To create a working system, just add /dev, /etc, and a Linux kernel. BusyBox provides a fairly complete POSIX environment for any small or embedded system.

BusyBox is extremely configurable. This allows you to include only the components you need, thereby reducing binary size. Run 'make config' or 'make menuconfig' to select the functionality that you wish to enable. Then run 'make' to compile BusyBox using your configuration.

After the compile has finished, you should use 'make install' to install BusyBox. This will install the 'bin/busybox' binary, in the target directory specified by CONFIG_PREFIX. CONFIG_PREFIX can be set when configuring BusyBox, or you can specify an alternative location at install time (i.e., with a command line like 'make CONFIG_PREFIX=/tmp/foo install'). If you enabled any applet installation scheme (either as symlinks or hardlinks), these will also be installed in the location pointed to by CONFIG_PREFIX.

USAGE

BusyBox is a mult-call binary. A mult-call binary is an executable program that performs the same job as more than one utility program. That means there is just a single BusyBox binary, but that single binary acts like a large number of utilities. This allows BusyBox to be smaller since all the buil-in utility programs (we call them applets) can share code for many common operations.

You can also invoke BusyBox by issuing a command as an argument on the command line. For example, entering

        /bin/busybox ls

will also cause BusyBox to behave as 'ls'.

Of course, adding '/bin/busybox' into every command would be painful. So most people will invoke BusyBox using links to the BusyBox binary.

For example, entering

        ln -s /bin/busybox ls
        ./ls

will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled into BusyBox). Generally speaking, you should never need to make all these links yourself, as the BusyBox build system will do this for you when you run the 'make install' command.

If you invoke BusyBox with no arguments, it will provide you with a list of the applets that have been compiled into your BusyBox binary.

COMMON OPTIONS

Most BusyBox applets support the --help argument to provide a terse runtime description of their behavior. If the CONFIG_FEATURE_VERBOSE_USAGE option has been enabled, more detailed usage information will also be available.

COMMANDS

Currently available applets include:

        [, [[, acpid, addgroup, adduser, adjtimex, ar, arch, arp, arping,
        ash, awk, base32, base64, basename, bb, bbconfig, bbsh, bc,
        blkdiscard, blkid, blockdev, brctl, bunzip2, busybox, bzcat, bzip2,
        cal, cat, chat, chattr, chgrp, chmod, chown, chpasswd, chpst,
        chroot, chrt, chvt, cksum, clear, cmp, comm, conspy, cp, cpio,
        crond, cryptpw, cttyhack, cut, date, dd, deallocvt, delgroup,
        deluser, depmod, devmem, df, dhcprelay, diff, dirname, dmesg,
        dnsdomainname, dos2unix, du, dumpkmap, dumpleases, echo, ed, egrep,
        eject, env, envdir, envuidgid, ether-wake, expand, expr, factor,
        fallocate, false, fatattr, fbset, fdflush, fdformat, fdisk,
        fgconsole, fgrep, find, findfs, flash_eraseall, flash_lock,
        flash_unlock, flashcp, flock, free, freeramdisk, fsck, fsfreeze,
        fstrim, fsync, ftpd, fuser, getopt, getty, ginit, grep, groups,
        gunzip, gzip, halt, hd, hdparm, head, hexdump, hexedit, hostname,
        httpd, hwclock, i2cdetect, i2cdump, i2cget, i2cset, i2ctransfer, id,
        ifconfig, ifdown, ifenslave, ifplugd, ifup, init, insmod, install,
        ionice, iostat, ip, ipaddr, ipcrm, ipcs, iplink, ipneigh, iproute,
        iprule, iptunnel, kbd_mode, kill, killall, killall5, last, less,
        link, linux32, linux64, linuxrc, ln, loadfont, loadkmap, login,
        logread, losetup, lpq, lpr, ls, lsattr, lsmod, lsof, lspci, lsscsi,
        lsusb, lzcat, lzma, lzop, lzopcat, makedevs, man, md5sum, mdev,
        mesg, microcom, mim, minips, mkdir, mkdosfs, mke2fs, mkfifo,
        mkfs.ext2, mkfs.reiser, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp,
        modinfo, modprobe, more, mount, mountpoint, mpstat, mt, mv, nameif,
        nanddump, nandwrite, nbd-client, nc, netcat, netstat, nice, nl,
        nmeter, nohup, nologin, nproc, nsenter, nslookup, ntpd, nuke,
        openvt, partprobe, passwd, paste, patch, pgrep, pidof, ping, ping6,
        pipe_progress, pivot_root, pkill, pmap, popmaildir, poweroff,
        powertop, printenv, printf, ps, pscan, pstree, pwd, pwdx,
        raidautorun, rdate, readahead, readlink, realpath, reboot, renice,
        reset, resize, resume, rev, rm, rmdir, rmmod, route, rtcwake,
        run-init, runlevel, rx, script, scriptreplay, sed, sendmail, seq,
        setarch, setconsole, setfattr, setfont, setkeycodes, setlogcons,
        setpriv, setserial, setsid, setuidgid, sh, sha1sum, sha256sum,
        sha3sum, sha512sum, showkey, shred, shuf, sleep, softlimit, sort,
        split, ssl_client, start-stop-daemon, stat, strings, stty, su, sum,
        svc, svok, swapoff, swapon, switch_root, sync, sysctl, tac, tail,
        tar, tc, tee, telnet, telnetd, test, tftp, tftpd, time, timeout,
        top, touch, tr, traceroute, traceroute6, true, truncate, ts, tty,
        ttysize, tunctl, tune2fs, ubiattach, ubidetach, ubimkvol, ubirename,
        ubirmvol, ubirsvol, ubiupdatevol, udhcpc, udhcpc6, udhcpd, uevent,
        umount, uname, uncompress, unexpand, uniq, unit, unix2dos, unlink,
        unlzma, unlzop, unshare, unxz, unzip, uptime, users, usleep,
        vconfig, vi, vlock, volname, w, wall, watch, watchdog, wc, wget,
        which, who, whoami, whois, xargs, xxd, xz, xzcat, yes, zcat, zcip

COMMAND DESCRIPTIONS

acpid

acpid [-df] [-c CONFDIR] [-l LOGFILE] [-a ACTIONFILE] [-M MAPFILE] [-e PROC_EVENT_FILE] [-p PIDFILE]

Listen to ACPI events and spawn specific helpers on event arrival

        -d      Log to stderr, not log file (implies -f)
        -f      Run in foreground
        -c DIR  Config directory [/etc/acpi]
        -e FILE /proc event file [/proc/acpi/event]
        -l FILE Log file [/var/log/acpid.log]
        -p FILE Pid file [/run/acpid.pid]
        -a FILE Action file [/etc/acpid.conf]
        -M FILE Map file [/etc/acpi.map]

Accept and ignore compatibility options -g -m -s -S -v

addgroup

addgroup [-g GID] [-S] [USER] GROUP

Add a group or add a user to a group

        -g GID  Group id
        -S      Create a system group

adduser

adduser [OPTIONS] USER [GROUP]

Create new user, or add USER to GROUP

        -h DIR          Home directory
        -g GECOS        GECOS field
        -s SHELL        Login shell
        -G GRP          Group
        -S              Create a system user
        -D              Don't assign a password
        -H              Don't create home directory
        -u UID          User id
        -k SKEL         Skeleton directory (/etc/skel)

adjtimex

adjtimex [-q] [-o OFS] [-f FREQ] [-p TCONST] [-t TICK]

Read or set kernel time variables. See adjtimex(2)

        -q      Quiet
        -o OFF  Time offset, microseconds
        -f FREQ Frequency adjust, integer kernel units (65536 is 1ppm)
        -t TICK Microseconds per tick, usually 10000
                (positive -t or -f values make clock run faster)
        -p TCONST

ar

ar x|p|t|r [-ov] ARCHIVE [FILE]...

Extract or list FILEs from an ar archive, or create it

        x       Extract
        p       Extract to stdout
        t       List
        r       Create
        -o      Restore mtime
        -v      Verbose

arch

arch

Print system architecture

arp

arp [-vn]   [-H HWTYPE] [-i IF] -a [HOSTNAME]
[-v]             [-i IF] -d HOSTNAME [pub]
[-v]    [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [temp]
[-v]    [-H HWTYPE] [-i IF] -s HOSTNAME HWADDR [netmask MASK] pub
[-v]    [-H HWTYPE] [-i IF] -Ds HOSTNAME IFACE [netmask MASK] pub

Manipulate ARP cache

        -a              Display (all) hosts
        -d              Delete ARP entry
        -s              Set new entry
        -v              Verbose
        -n              Don't resolve names
        -i IF           Network interface
        -D              Read HWADDR from IFACE
        -A,-p AF        Protocol family
        -H HWTYPE       Hardware address type

arping

arping [-fqbDUA] [-c CNT] [-w TIMEOUT] [-I IFACE] [-s SRC_IP] DST_IP

Send ARP requests/replies

        -f              Quit on first ARP reply
        -q              Quiet
        -b              Keep broadcasting, don't go unicast
        -D              Exit with 1 if DST_IP replies
        -U              Unsolicited ARP mode, update your neighbors
        -A              ARP answer mode, update your neighbors
        -c N            Stop after sending N ARP requests
        -w TIMEOUT      Seconds to wait for ARP reply
        -I IFACE        Interface to use (default eth0)
        -s SRC_IP       Sender IP address
        DST_IP          Target IP address

ash

ash [-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS] / -s [ARGS]]

Unix shell interpreter

awk

awk [OPTIONS] [AWK_PROGRAM] [FILE]...

        -v VAR=VAL      Set variable
        -F SEP          Use SEP as field separator
        -f FILE         Read program from FILE
        -e AWK_PROGRAM

base32

base32 [-d] [-w COL] [FILE]

Base32 encode or decode FILE to standard output -d Decode data
-w COL Wrap lines at COL (default 76, 0 disables)

base64

base64 [-d] [-w COL] [FILE]

Base64 encode or decode FILE to standard output -d Decode data
-w COL Wrap lines at COL (default 76, 0 disables)

basename

basename FILE [SUFFIX]

Strip directory path and .SUFFIX from FILE

bb

bb [-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS] / -s [ARGS]]

Unix shell interpreter

bbconfig

bbconfig

Print the config file used by busybox build

bbsh

bbsh [-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS] / -s [ARGS]]

Unix shell interpreter

bc

bc [-sqlw] FILE...

Arbitrary precision calculator

        -q      Quiet
        -l      Load standard math library
        -s      Be POSIX compatible
        -w      Warn if extensions are used

$BC_LINE_LENGTH changes output width

blkdiscard

blkdiscard [-o OFS] [-l LEN] [-s] DEVICE

Discard sectors on DEVICE

        -o OFS  Byte offset into device
        -l LEN  Number of bytes to discard
        -s      Perform a secure discard

blkid

blkid [BLOCKDEV]...

Print UUIDs of all filesystems

blockdev

blockdev OPTION BLOCKDEV

        --setro         Set ro
        --setrw         Set rw
        --getro         Get ro
        --getss         Get sector size
        --getbsz        Get block size
        --setbsz BYTES  Set block size
        --getsz         Get device size in 512-byte sectors
        --getsize64     Get device size in bytes
        --flushbufs     Flush buffers
        --rereadpt      Reread partition table

brctl

brctl COMMAND [BRIDGE [ARGS]]

Manage ethernet bridges Commands:

        show [BRIDGE]...        Show bridges
        addbr BRIDGE            Create BRIDGE
        delbr BRIDGE            Delete BRIDGE
        addif BRIDGE IFACE      Add IFACE to BRIDGE
        delif BRIDGE IFACE      Delete IFACE from BRIDGE
        showmacs BRIDGE                 List MAC addresses
        showstp BRIDGE                  Show STP info
        stp BRIDGE 1/yes/on|0/no/off    Set STP on/off
        setageing BRIDGE SECONDS        Set ageing time
        setfd BRIDGE SECONDS            Set bridge forward delay
        sethello BRIDGE SECONDS         Set hello time
        setmaxage BRIDGE SECONDS        Set max message age
        setbridgeprio BRIDGE PRIO       Set bridge priority
        setportprio BRIDGE IFACE PRIO   Set port priority
        setpathcost BRIDGE IFACE COST   Set path cost

bunzip2

bunzip2 [-cfk] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -k      Keep input files

bzcat

bzcat [FILE]...

Decompress to stdout

bzip2

bzip2 [-cfkdt123456789] [FILE]...

Compress FILEs (or stdin) with bzip2 algorithm

        -1..9   Compression level
        -d      Decompress
        -t      Test file integrity
        -c      Write to stdout
        -f      Force
        -k      Keep input files

cal

cal [-jy] [[MONTH] YEAR]

Display a calendar

        -j      Use julian dates
        -y      Display the entire year

cat

cat [-nbvteA] [FILE]...

Print FILEs to stdout

        -n      Number output lines
        -b      Number nonempty lines
        -v      Show nonprinting characters as ^x or M-x
        -t      ...and tabs as ^I
        -e      ...and end lines with $
        -A      Same as -vte

chat

chat EXPECT [SEND [EXPECT [SEND...]]]

Useful for interacting with a modem connected to stdin/stdout. A script consists of ``expec-send'' argument pairs. Example:

chat '' ATZ OK ATD123456 CONNECT '' ogin: pppuser word: ppppass '~'

chattr

chattr [-R] [-v VERSION] [-+=AacDdijsStTu] FILE...

Change ext2 file attributes

        -R      Recurse
        -v VER  Set version/generation number
Modifiers:

        -,+,=   Remove/add/set attributes
Attributes:

        A       Don't track atime
        a       Append mode only
        c       Enable compress
        D       Write dir contents synchronously
        d       Don't backup with dump
        i       Cannot be modified (immutable)
        j       Write all data to journal first
        s       Zero disk storage when deleted
        S       Write synchronously
        t       Disable tail-merging of partial blocks with other files
        u       Allow file to be undeleted

chgrp

chgrp [-RhLHPcvf]... GROUP FILE...

Change the group membership of each FILE to GROUP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Don't traverse symlinks (default)
        -c      List changed files
        -v      Verbose
        -f      Hide errors

chmod

chmod [-Rcvf] MODE[,MODE]... FILE...

Each MODE is one or more of the letters ugoa, one of the symbols +-= and one or more of the letters rwxst

        -R      Recurse
        -c      List changed files
        -v      List all files
        -f      Hide errors

chown

chown [-RhLHPcvf]... USER[:[GRP]] FILE...

Change the owner and/or group of each FILE to USER and/or GRP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Don't traverse symlinks (default)
        -c      List changed files
        -v      List all files
        -f      Hide errors

chpasswd

chpasswd [-me] [-c ALG] [-R DIR]

Read user:password from stdin and update /etc/passwd

        -e      Supplied passwords are in encrypted form
        -m      Encrypt using md5, not des
        -c ALG  des,md5,sha256/512 (default des)
        -R DIR  Directory to chroot into

chpst

chpst [-vP012] [-u USER[:GRP]] [-U USER[:GRP]] [-e DIR] [-/ DIR] [-n NICE] [-m BYTES] [-d BYTES] [-o N]
[-p N] [-f BYTES] [-c BYTES] PROG ARGS

Change the process state, run PROG

        -u USER[:GRP]   Set uid and gid
        -U USER[:GRP]   Set $UID and $GID in environment
        -e DIR          Set environment variables as specified by files
                        in DIR: file=1st_line_of_file
        -/ DIR          Chroot to DIR
        -n NICE         Add NICE to nice value
        -m BYTES        Same as -d BYTES -s BYTES -l BYTES
        -d BYTES        Limit data segment
        -o N            Limit number of open files per process
        -p N            Limit number of processes per uid
        -f BYTES        Limit output file sizes
        -c BYTES        Limit core file size
        -v              Verbose
        -P              Create new process group
        -0              Close stdin
        -1              Close stdout
        -2              Close stderr

chroot

chroot NEWROOT [PROG ARGS]

Run PROG with root directory set to NEWROOT

chrt

chrt -m | -p [PRIO] PID | [-rfobi] PRIO PROG ARGS

Change scheduling priority and class for a process

        -m      Show min/max priorities
        -p      Operate on PID
        -r      Set SCHED_RR class
        -f      Set SCHED_FIFO class
        -o      Set SCHED_OTHER class
        -b      Set SCHED_BATCH class
        -i      Set SCHED_IDLE class

chvt

chvt N

Change the foreground virtual terminal to /dev/ttyN

cksum

cksum FILE...

Calculate the CRC32 checksums of FILEs

clear

clear

Clear screen

cmp

cmp [-l] [-s] FILE1 [FILE2 [SKIP1 [SKIP2]]]

Compare FILE1 with FILE2 (or stdin)

        -l      Write the byte numbers (decimal) and values (octal)
                for all differing bytes
        -s      Quiet

comm

comm [-123] FILE1 FILE2

Compare FILE1 with FILE2

        -1      Suppress lines unique to FILE1
        -2      Suppress lines unique to FILE2
        -3      Suppress lines common to both files

conspy

conspy [-vcsndfFQ] [-x COL] [-y LINE] [CONSOLE_NO]

A tex-mode VNC like program for Linux virtual consoles. To exit, quickly press ESC 3 times.

        -v      Don't send keystrokes to the console
        -c      Create missing /dev/{tty,vcsa}N
        -s      Open a SHELL session
        -n      Black & white
        -d      Dump console to stdout
        -f      Follow cursor
        -F      Assume console is on a framebuffer device
        -Q      Disable exit on ESC-ESC-ESC
        -x COL  Starting column
        -y LINE Starting line

cp

cp [-arPLHpfilsTu] SOURCE... DEST

Copy SOURCE(s) to DEST

        -a      Same as -dpR
        -R,-r   Recurse
        -d,-P   Preserve symlinks (default if -R)
        -L      Follow all symlinks
        -H      Follow symlinks on command line
        -p      Preserve file attributes if possible
        -f      Overwrite
        -i      Prompt before overwrite
        -l,-s   Create (sym)links
        -T      Treat DEST as a normal file
        -u      Copy only newer files

cpio

cpio [-dmvu] [-F FILE] [-R USER[:GRP]] [-H newc] [-tio] [-p DIR] [EXTR_FILE]...

Extract (-i) or list (-t) files from a cpio archive, or take file list from stdin and create an archive (-o) or copy files (-p)

Main operation mode:

        -t      List
        -i      Extract EXTR_FILEs (or all)
        -o      Create (requires -H newc)
        -p DIR  Copy files to DIR
Options:

        -H newc Archive format
        -d      Make leading directories
        -m      Restore mtime
        -v      Verbose
        -u      Overwrite
        -F FILE Input (-t,-i,-p) or output (-o) file
        -R USER[:GRP]   Set owner of created files
        -L      Dereference symlinks
        -0      Input is separated by NULs

crond

crond [-fbS] [-l N] [-d N] [-L LOGFILE] [-c DIR]

        -f      Foreground
        -b      Background (default)
        -S      Log to syslog (default)
        -l N    Set log level. Most verbose 0, default 8
        -d N    Set log level, log to stderr
        -L FILE Log to FILE
        -c DIR  Cron dir. Default:/var/spool/cron/crontabs

cryptpw

cryptpw [-s] [-p N] [-m TYPE] [-S SALT] [PASSWORD] [SALT]

Print crypt(3) hashed PASSWORD

        -P N    Read password from fd N
        -m TYPE des,md5,sha256/512 (default des)
        -S SALT

cttyhack

cttyhack [PROG ARGS]

Give PROG a controlling tty if possible. Example for /etc/inittab (for busybox init): ::respawn:/bin/cttyhack /bin/sh
Giving controlling tty to shell running with PID 1: $ exec cttyhack sh
Starting interactive shell from boot shell script:

        setsid cttyhack sh

cut

cut [OPTIONS] [FILE]...

Print selected fields from each input FILE to stdout

        -b LIST Output only bytes from LIST
        -c LIST Output only characters from LIST
        -d CHAR Use CHAR instead of tab as the field delimiter
        -s      Output only the lines containing delimiter
        -f N    Print only these fields
        -n      Ignored

date

date [OPTIONS] [+FMT] [[-s] TIME]

Display time (using +FMT), or set time

        -u              Work in UTC (don't convert to local time)
        [-s] TIME       Set time to TIME
        -d TIME         Display TIME, not 'now'
        -D FMT          FMT (strptime format) for -s/-d TIME conversion
        -r FILE         Display last modification time of FILE
        -R              Output RFC-2822 date
        -I[SPEC]        Output ISO-8601 date
                        SPEC=date (default), hours, minutes, seconds or ns

Recognized TIME formats:

        @seconds_since_1970
        hh:mm[:ss]
        [YYYY.]MM.DD-hh:mm[:ss]
        YYYY-MM-DD hh:mm[:ss]
        [[[[[YY]YY]MM]DD]hh]mm[.ss]
        'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead

dd

Copy a file with converting and formatting

        if=FILE         Read from FILE instead of stdin
        of=FILE         Write to FILE instead of stdout
        bs=N            Read and write N bytes at a time
        ibs=N           Read N bytes at a time
        obs=N           Write N bytes at a time
        count=N         Copy only N input blocks
        skip=N          Skip N input blocks
        seek=N          Skip N output blocks
        conv=notrunc    Don't truncate output file
        conv=noerror    Continue after read errors
        conv=sync       Pad blocks with zeros
        conv=fsync      Physically write data out before finishing
        conv=swab       Swap every pair of bytes
        iflag=skip_bytes        skip=N is in bytes
        oflag=seek_bytes        seek=N is in bytes
        iflag=direct    O_DIRECT input
        oflag=direct    O_DIRECT output
        iflag=fullblock Read full blocks
        oflag=append    Open output in append mode
        status=noxfer   Suppress rate output
        status=none     Suppress all output

N may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G

deallocvt

deallocvt [N]

Deallocate unused virtual terminal /dev/ttyN

delgroup

delgroup [USER] GROUP

Delete group GROUP from the system or user USER from group GROUP

deluser

deluser [--remove-home] USER

Delete USER from the system

depmod

depmod [-n]

Generate modules.dep.bb

        -n      Dry run: print file to stdout

devmem

devmem ADDRESS [WIDTH [VALUE]]

Read/write from physical address

        ADDRESS Address to act upon
        WIDTH   Width (8/16/...)
        VALUE   Data to be written

df

df [-PkmhTai] [-B SIZE] [FILESYSTEM]...

Print filesystem usage statistics

        -P      POSIX output format
        -k      1024-byte blocks (default)
        -m      1M-byte blocks
        -h      Human readable (e.g. 1K 243M 2G)
        -T      Print filesystem type
        -a      Show all filesystems
        -i      Inodes
        -B SIZE Blocksize

dhcprelay

dhcprelay CLIENT_IFACE[,CLIENT_IFACE2]... SERVER_IFACE [SERVER_IP]

Relay DHCP requests between clients and server

diff

diff [-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2

Compare files line by line and output the differences between them. This implementation supports unified diffs only.

        -a      Treat all files as text
        -b      Ignore changes in the amount of whitespace
        -B      Ignore changes whose lines are all blank
        -d      Try hard to find a smaller set of changes
        -i      Ignore case differences
        -L      Use LABEL instead of the filename in the unified header
        -N      Treat absent files as empty
        -q      Output only whether files differ
        -r      Recurse
        -S      Start with FILE when comparing directories
        -T      Make tabs line up by prefixing a tab when necessary
        -s      Report when two files are the same
        -t      Expand tabs to spaces in output
        -U      Output LINES lines of context
        -w      Ignore all whitespace

dirname

dirname FILENAME

Strip no-directory suffix from FILENAME

dmesg

dmesg [-c] [-n LEVEL] [-s SIZE]

Print or control the kernel ring buffer

        -c              Clear ring buffer after printing
        -n LEVEL        Set console logging level
        -s SIZE         Buffer size
        -r              Print raw message buffer

dos2unix

dos2unix [-ud] [FILE]

Convert FILE i-place from DOS to Unix format. When no file is given, use stdin/stdout.

        -u      dos2unix
        -d      unix2dos

du

du [-aHLdclsxhmk] [FILE]...

Summarize disk space used for each FILE and/or directory

        -a      Show file sizes too
        -L      Follow all symlinks
        -H      Follow symlinks on command line
        -d N    Limit output to directories (and files with -a) of depth < N
        -c      Show grand total
        -l      Count sizes many times if hard linked
        -s      Display only a total for each argument
        -x      Skip directories on different filesystems
        -h      Sizes in human readable format (e.g., 1K 243M 2G)
        -m      Sizes in megabytes
        -k      Sizes in kilobytes (default)

dumpkmap

dumpkmap > keymap

Print a binary keyboard translation table to stdout

dumpleases

dumpleases [-r|-a] [-d] [-f LEASEFILE]

Display DHCP leases granted by udhcpd

        -f FILE Lease file
        -r      Show remaining time
        -a      Show expiration time
        -d      Show time in seconds

echo

echo [-neE] [ARG]...

Print the specified ARGs to stdout

        -n      Suppress trailing newline
        -e      Interpret backslash escapes (i.e., t=tab)
        -E      Don't interpret backslash escapes (default)

ed

ed [FILE]

eject

eject [-t] [-T] [DEVICE]

Eject DEVICE or default /dev/cdrom

        -s      SCSI device
        -t      Close tray
        -T      Open/close tray (toggle)

env

env [-iu] [-] [name=value]... [PROG ARGS]

Print the current environment or run PROG after setting up the specified environment

        -, -i   Start with an empty environment
        -u      Remove variable from the environment

envdir

envdir DIR PROG ARGS

Set various environment variables as specified by files in the directory DIR, run PROG

envuidgid

envuidgid USER PROG ARGS

Set $UID to USER's uid and $GID to USER's gid, run PROG

ethe-wake

ethe-wake [-b] [-i IFACE] [-p aa:bb:cc:dd[:ee:ff]/a.b.c.d] MAC

Send a magic packet to wake up sleeping machines. MAC must be a station address (00:11:22:33:44:55) or a hostname with a known 'ethers' entry.

        -b              Broadcast the packet
        -i IFACE        Interface to use (default eth0)
        -p PASSWORD     Append four or six byte PASSWORD to the packet

expand

expand [-i] [-t N] [FILE]...

Convert tabs to spaces, writing to stdout

        -i      Don't convert tabs after non blanks
        -t      Tabstops every N chars

expr

expr EXPRESSION

Print the value of EXPRESSION to stdout

EXPRESSION may be:

        ARG1 | ARG2     ARG1 if it is neither null nor 0, otherwise ARG2
        ARG1 & ARG2     ARG1 if neither argument is null or 0, otherwise 0
        ARG1 < ARG2     1 if ARG1 is less than ARG2, else 0. Similarly:
        ARG1 <= ARG2
        ARG1 = ARG2
        ARG1 != ARG2
        ARG1 >= ARG2
        ARG1 > ARG2
        ARG1 + ARG2     Sum of ARG1 and ARG2. Similarly:
        ARG1 - ARG2
        ARG1 * ARG2
        ARG1 / ARG2
        ARG1 % ARG2
        STRING : REGEXP         Anchored pattern match of REGEXP in STRING
        match STRING REGEXP     Same as STRING : REGEXP
        substr STRING POS LENGTH Substring of STRING, POS counted from 1
        index STRING CHARS      Index in STRING where any CHARS is found, or 0
        length STRING           Length of STRING
        quote TOKEN             Interpret TOKEN as a string, even if
                                it is a keyword like 'match' or an
                                operator like '/'
        (EXPRESSION)            Value of EXPRESSION

Beware that many operators need to be escaped or quoted for shells. Comparisons are arithmetic if both ARGs are numbers, else lexicographical. Pattern matches return the string matched between ( and ) or null; if ( and ) are not used, they return the number of characters matched or 0.

factor

factor [NUMBER]...

Print prime factors

fallocate

fallocate [-o OFS] -l LEN FILE

Preallocate space for FILE

        -o OFS  Offset of range
        -l LEN  Length of range

fatattr

fatattr [-+rhsvda] FILE...

Change file attributes on FAT filesystem

        -       Clear attributes
        +       Set attributes
        r       Read only
        h       Hidden
        s       System
        v       Volume label
        d       Directory
        a       Archive

fbset

fbset [OPTIONS] [MODE]

Show and modify frame buffer settings

fdflush

fdflush DEVICE

Force floppy disk drive to detect disk change

fdformat

fdformat [-n] DEVICE

Format floppy disk

        -n      Don't verify after format

fdisk

fdisk [-ul] [-C CYLINDERS] [-H HEADS] [-S SECTORS] [-b SSZ] DISK

Change partition table

        -u              Start and End are in sectors (instead of cylinders)
        -l              Show partition table for each DISK, then exit
        -b 2048         (for certain MO disks) use 2048-byte sectors
        -C CYLINDERS    Set number of cylinders/heads/sectors
        -H HEADS        Typically 255
        -S SECTORS      Typically 63

fgconsole

fgconsole

Get active console

find

find [-HL] [PATH]... [OPTIONS] [ACTIONS]

Search for files and perform actions on them. First failed action stops processing of current file. Defaults: PATH is current directory, action is '-print'

        -L,-follow      Follow symlinks
        -H              ...on command line only
        -xdev           Don't descend directories on other filesystems
        -maxdepth N     Descend at most N levels. -maxdepth 0 applies
                        actions to command line arguments only
        -mindepth N     Don't act on first N levels
        -depth          Act on directory *after* traversing it

Actions:

        ( ACTIONS )     Group actions for -o / -a
        ! ACT           Invert ACT's success/failure
        ACT1 [-a] ACT2  If ACT1 fails, stop, else do ACT2
        ACT1 -o ACT2    If ACT1 succeeds, stop, else do ACT2
                        Note: -a has higher priority than -o
        -name PATTERN   Match file name (w/o directory name) to PATTERN
        -iname PATTERN  Case insensitive -name
        -path PATTERN   Match path to PATTERN
        -ipath PATTERN  Case insensitive -path
        -regex PATTERN  Match path to regex PATTERN
        -type X         File type is X (one of: f,d,l,b,c,s,p)
        -executable     File is executable
        -perm MASK      At least one mask bit (+MASK), all bits (-MASK),
                        or exactly MASK bits are set in file's mode
        -mtime DAYS     mtime is greater than (+N), less than (-N),
                        or exactly N days in the past
        -mmin MINS      mtime is greater than (+N), less than (-N),
                        or exactly N minutes in the past
        -newer FILE     mtime is more recent than FILE's
        -inum N         File has inode number N
        -user NAME/ID   File is owned by given user
        -group NAME/ID  File is owned by given group
        -size N[bck]    File size is N (c:bytes,k:kbytes,b:512 bytes(def.))
                        +/-N: file size is bigger/smaller than N
        -links N        Number of links is greater than (+N), less than (-N),
                        or exactly N
        -empty          Match empty file/directory
        -prune          If current file is directory, don't descend into it
If none of the following actions is specified, -print is assumed
        -print          Print file name
        -print0         Print file name, NUL terminated
        -exec CMD ARG ; Run CMD with all instances of {} replaced by
                        file name. Fails if CMD exits with nonzero
        -exec CMD ARG + Run CMD with {} replaced by list of file names
        -delete         Delete current file/directory. Turns on -depth option
        -quit           Exit

findfs

findfs LABEL=label or UUID=uuid

Find a filesystem device based on a label or UUID

flash_eraseall

flash_eraseall [-jNq] MTD_DEVICE

Erase an MTD device

        -j      Format the device for jffs2
        -N      Don't skip bad blocks
        -q      Don't display progress messages

flash_lock

flash_lock MTD_DEVICE OFFSET SECTORS

Lock part or all of an MTD device. If SECTORS is -1, then all sectors will be locked, regardless of the value of OFFSET

flash_unlock

flash_unlock MTD_DEVICE

Unlock an MTD device

flashcp

flashcp -v FILE MTD_DEVICE

Copy an image to MTD device

        -v      Verbose

flock

flock [-sxun] FD|{FILE [-c] PROG ARGS}

[Un]lock file descriptor, or lock FILE, run PROG

        -s      Shared lock
        -x      Exclusive lock (default)
        -u      Unlock FD
        -n      Fail rather than wait

free

free [-b/k/m/g]

Display the amount of free and used system memory

freeramdisk

freeramdisk DEVICE

Free all memory used by the specified ramdisk

fsck

fsck [-ANPRTV] [-t FSTYPE] [FS_OPTS] [BLOCKDEV]...

Check and repair filesystems

        -A      Walk /etc/fstab and check all filesystems
        -N      Don't execute, just show what would be done
        -P      With -A, check filesystems in parallel
        -R      With -A, skip the root filesystem
        -T      Don't show title on startup
        -V      Verbose
        -t TYPE List of filesystem types to check

fsfreeze

fsfreeze --[un]freeze MOUNTPOINT

Flush and halt writes to MOUNTPOINT

fstrim

fstrim [OPTIONS] MOUNTPOINT

        -o OFFSET       Offset in bytes to discard from
        -l LEN          Bytes to discard
        -m MIN          Minimum extent length
        -v              Print number of discarded bytes

fsync

fsync [-d] FILE...

Write all buffered blocks in FILEs to disk

        -d      Avoid syncing metadata

ftpd

ftpd [-wvS] [-a USER] [-t N] [-T N] [DIR]

FTP server. Chroots to DIR, if this fails (run by no-root), cds to it. Should be used as inetd service, inetd.conf line: 21 stream tcp nowait root ftpd ftpd /files/to/serve
Can be run from tcpsvd:

        tcpsvd -vE 0.0.0.0 21 ftpd /files/to/serve

        -w      Allow upload
        -A      No login required, client access occurs under ftpd's UID
        -a USER Enable 'anonymous' login and map it to USER
        -v      Log errors to stderr. -vv: verbose log
        -S      Log errors to syslog. -SS: verbose log
        -t,-T N Idle and absolute timeout

fuser

fuser [-msk46] [-SIGNAL] FILE or PORT/PROTO

Find processes which use FILEs or PORTs

        -m      Find processes which use same fs as FILEs
        -4,-6   Search only IPv4/IPv6 space
        -s      Don't display PIDs
        -k      Kill found processes
        -SIGNAL Signal to send (default: KILL)

getopt

getopt [OPTIONS] [--] OPTSTRING PARAMS

        -a              Allow long options starting with single -
        -l LOPT[,...]   Long options to recognize
        -n PROGNAME     The name under which errors are reported
        -o OPTSTRING    Short options to recognize
        -q              No error messages on unrecognized options
        -Q              No normal output
        -s SHELL        Set shell quoting conventions
        -T              Version test (exits with 4)
        -u              Don't quote output

Example:

O=`getopt -l bb: - ab:c:: ``$@''` || exit 1 eval set - ``$O'' while true; do         case ``$1'' in
        -a)     echo A; shift;;
        -b|--bb) echo ``B:'$2'''; shift 2;;
        -c)     case ``$2'' in
                "``)    echo C; shift 2;;
                *)      echo ''C:'$2'"; shift 2;;
                esac;;
        --)     shift; break;;
        *)      echo Error; exit 1;;
        esac
done

getty

getty [OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]

Open TTY, prompt for login name, then invoke /bin/login

        -h              Enable hardware RTS/CTS flow control
        -L              Set CLOCAL (ignore Carrier Detect state)
        -m              Get baud rate from modem's CONNECT status message
        -n              Don't prompt for login name
        -w              Wait for CR or LF before sending /etc/issue
        -i              Don't display /etc/issue
        -f ISSUE_FILE   Display ISSUE_FILE instead of /etc/issue
        -l LOGIN        Invoke LOGIN instead of /bin/login
        -t SEC          Terminate after SEC if no login name is read
        -I INITSTR      Send INITSTR before anything else
        -H HOST         Log HOST into the utmp file as the hostname

BAUD_RATE of 0 leaves it unchanged

grep

grep [-HhnlLoqvsrRiwFEz] [-m N] [-A/B/C N] PATTERN/-e PATTERN.../-f FILE [FILE]...

Search for PATTERN in FILEs (or stdin)

        -H      Add 'filename:' prefix
        -h      Do not add 'filename:' prefix
        -n      Add 'line_no:' prefix
        -l      Show only names of files that match
        -L      Show only names of files that don't match
        -c      Show only count of matching lines
        -o      Show only the matching part of line
        -q      Quiet. Return 0 if PATTERN is found, 1 otherwise
        -v      Select non-matching lines
        -s      Suppress open and read errors
        -r      Recurse
        -R      Recurse and dereference symlinks
        -i      Ignore case
        -w      Match whole words only
        -x      Match whole lines only
        -F      PATTERN is a literal (not regexp)
        -E      PATTERN is an extended regexp
        -z      Input is NUL terminated
        -m N    Match up to N times per file
        -A N    Print N lines of trailing context
        -B N    Print N lines of leading context
        -C N    Same as '-A N -B N'
        -e PTRN Pattern to match
        -f FILE Read pattern from file

groups

groups [USER]

Print the group memberships of USER or for the current process

gunzip

gunzip [-cfkt] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -k      Keep input files
        -t      Test file integrity

gzip

gzip [-cfkdt123456789] [FILE]...

Compress FILEs (or stdin)

        -1..9   Compression level
        -d      Decompress
        -t      Test file integrity
        -c      Write to stdout
        -f      Force
        -k      Keep input files

halt

halt [-d DELAY] [-nfw]

Halt the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)
        -w      Only write a wtmp record

hd

hd FILE...

hd is an alias for hexdump -C

hdparm

hdparm [OPTIONS] [DEVICE]

        -a      Get/set fs readahead
        -A      Set drive read-lookahead flag (0/1)
        -b      Get/set bus state (0 == off, 1 == on, 2 == tristate)
        -B      Set Advanced Power Management setting (1-255)
        -c      Get/set IDE 32-bit IO setting
        -C      Check IDE power mode status
        -d      Get/set using_dma flag
        -D      Enable/disable drive defect-mgmt
        -f      Flush buffer cache for device on exit
        -g      Display drive geometry
        -h      Display terse usage information
        -i      Display drive identification
        -I      Detailed/current information directly from drive
        -k      Get/set keep_settings_over_reset flag (0/1)
        -K      Set drive keep_features_over_reset flag (0/1)
        -L      Set drive doorlock (0/1) (removable harddisks only)
        -m      Get/set multiple sector count
        -n      Get/set ignore-write-errors flag (0/1)
        -p      Set PIO mode on IDE interface chipset (0,1,2,3,4,...)
        -P      Set drive prefetch count
        -Q      Get/set DMA tagged-queuing depth (if supported)
        -r      Get/set readonly flag (DANGEROUS to set)
        -R      Register an IDE interface (DANGEROUS)
        -S      Set standby (spindown) timeout
        -t      Perform device read timings
        -T      Perform cache read timings
        -u      Get/set unmaskirq flag (0/1)
        -U      Unregister an IDE interface (DANGEROUS)
        -v      Defaults; same as -mcudkrag for IDE drives
        -V      Display program version and exit immediately
        -w      Perform device reset (DANGEROUS)
        -W      Set drive write-caching flag (0/1) (DANGEROUS)
        -x      Tristate device for hotswap (0/1) (DANGEROUS)
        -X      Set IDE xfer mode (DANGEROUS)
        -y      Put IDE drive in standby mode
        -Y      Put IDE drive to sleep
        -Z      Disable Seagate auto-powersaving mode
        -z      Reread partition table

head

head [OPTIONS] [FILE]...

Print first 10 lines of each FILE (or stdin) to stdout. With more than one FILE, precede each with a filename header.

        -n N[kbm]       Print first N lines
        -n -N[kbm]      Print all except N last lines
        -c [-]N[kbm]    Print first N bytes
        -q              Never print headers
        -v              Always print headers

N may be suffixed by k (x1024), b (x512), or m (x1024^2).

hexdump

hexdump [-bcdoxCv] [-e FMT] [-f FMT_FILE] [-n LEN] [-s OFS] [FILE]...

Display FILEs (or stdin) in a user specified format

        -b              1-byte octal display
        -c              1-byte character display
        -d              2-byte decimal display
        -o              2-byte octal display
        -x              2-byte hex display
        -C              hex+ASCII 16 bytes per line
        -v              Show all (no dup folding)
        -e FORMAT_STR   Example: '16/1 "%02x|""n"'
        -f FORMAT_FILE
        -n LENGTH       Show only first LENGTH bytes
        -s OFFSET       Skip OFFSET bytes

hexedit

hexedit FILE

Edit FILE in hexadecimal

hostname

hostname [-sidf] [HOSTNAME | -F FILE]

Show or set hostname or DNS domain name

        -s      Short
        -i      Addresses for the hostname
        -d      DNS domain name
        -f      Fully qualified domain name
        -F FILE Use FILE's content as hostname

httpd

httpd [-ifv[v]] [-c CONFFILE] [-p [IP:]PORT] [-u USER[:GRP]] [-r REALM] [-h HOME] or httpd -d/-e/-m STRING

Listen for incoming HTTP requests

        -i              Inetd mode
        -f              Don't daemonize
        -v[v]           Verbose
        -p [IP:]PORT    Bind to IP:PORT (default *:80)
        -u USER[:GRP]   Set uid/gid after binding to port
        -r REALM        Authentication Realm for Basic Authentication
        -h HOME         Home directory (default .)
        -c FILE         Configuration file (default {/etc,HOME}/httpd.conf)
        -m STRING       MD5 crypt STRING
        -e STRING       HTML encode STRING
        -d STRING       URL decode STRING

hwclock

hwclock [-swul] [--systz] [-f DEV]

Show or set hardware clock (RTC)

        -s      Set system time from RTC
        -w      Set RTC from system time
        --systz Set in-kernel timezone, correct system time
                if RTC is kept in local time
        -f DEV  Use specified device (e.g. /dev/rtc2)
        -u      Assume RTC is kept in UTC
        -l      Assume RTC is kept in local time
                (if neither is given, read from /var/lib/hwclock/adjtime)

i2cdetect

i2cdetect -l | -F I2CBUS | [-ya] [-q|-r] I2CBUS [FIRST LAST]

Detect I2C chips

        -l      List installed buses
        -F BUS# List functionalities on this bus
        -y      Disable interactive mode
        -a      Force scanning of non-regular addresses
        -q      Use smbus quick write commands for probing (default)
        -r      Use smbus read byte commands for probing
        FIRST and LAST limit probing range

i2cdump

i2cdump [-fy] [-r FIRST-LAST] BUS ADDR [MODE]

Examine I2C registers

        I2CBUS  I2C bus number
        ADDRESS 0x03-0x77
MODE is:

        b       Byte (default)
        w       Word
        W       Word on even register addresses
        i       I2C block
        s       SMBus block
        c       Consecutive byte
        Append p for SMBus PEC

        -f      Force access
        -y      Disable interactive mode
        -r      Limit the number of registers being accessed

i2cget

i2cget [-fy] BUS CHI-ADDRESS [DATA-ADDRESS [MODE]]

Read from I2C/SMBus chip registers

        I2CBUS  I2C bus number
        ADDRESS 0x03-0x77
MODE is:

        b       Read byte data (default)
        w       Read word data
        c       Write byte/read byte
        Append p for SMBus PEC

        -f      Force access
        -y      Disable interactive mode

i2cset

i2cset [-fy] [-m MASK] BUS CHI-ADDRESS DAT-ADDRESS [VALUE] ... [MODE]

Set I2C registers

        I2CBUS  I2C bus number
        ADDRESS 0x03-0x77
MODE is:

        c       Byte, no value
        b       Byte data (default)
        w       Word data
        i       I2C block data
        s       SMBus block data
        Append p for SMBus PEC

        -f      Force access
        -y      Disable interactive mode
        -r      Read back and compare the result
        -m MASK Mask specifying which bits to write

i2ctransfer

i2ctransfer [-fay] I2CBUS {rLENGTH[@ADDR] | wLENGTH[@ADDR] DATA...}...

Read/write I2C data in one transfer

        -f      Force access to busy addresses
        -a      Force access to non-regular addresses
        -y      Disable interactive mode

id

id [-ugGnr] [USER]

Print information about USER or the current user

        -u      User ID
        -g      Group ID
        -G      Supplementary group IDs
        -n      Print names instead of numbers
        -r      Print real ID instead of effective ID

ifconfig

ifconfig [-a] [IFACE] [ADDRESS]

Configure a network interface

        [add ADDRESS[/PREFIXLEN]]
        [del ADDRESS[/PREFIXLEN]]
        [[-]broadcast [ADDRESS]] [[-]pointopoint [ADDRESS]]
        [netmask ADDRESS] [dstaddr ADDRESS]
        [outfill NN] [keepalive NN]
        [hw ether|infiniband ADDRESS] [metric NN] [mtu NN]
        [[-]trailers] [[-]arp] [[-]allmulti]
        [multicast] [[-]promisc] [txqueuelen NN] [[-]dynamic]
        [mem_start NN] [io_addr NN] [irq NN]
        [up|down] ...

ifdown

ifdown [-nmvf] [-i FILE] -a | IFACE...

        -a      Deconfigure all interfaces
        -i FILE Use FILE instead of /etc/network/interfaces
        -n      Dry run
                (note: doesn't disable mappings)
        -m      Don't run any mappings
        -v      Print out what would happen before doing it
        -f      Force

ifenslave

ifenslave [-cdf] MASTER_IFACE SLAVE_IFACE...

Configure network interfaces for parallel routing

        -c      Change active slave
        -d      Remove slave interface from bonding device
        -f      Force, even if interface is not Ethernet

ifplugd

ifplugd [OPTIONS]

Network interface plug detection daemon

        -n              Don't daemonize
        -s              Don't log to syslog
        -i IFACE        Interface
        -f/-F           Treat link detection error as link down/link up
                        (otherwise exit on error)
        -a              Don't up interface at each link probe
        -M              Monitor creation/destruction of interface
                        (otherwise it must exist)
        -r PROG         Script to run
        -x ARG          Extra argument for script
        -I              Don't exit on nonzero exit code from script
        -p              Don't run "up" script on startup
        -q              Don't run "down" script on exit
        -l              Always run script on startup
        -t SECS         Poll time in seconds
        -u SECS         Delay before running script after link up
        -d SECS         Delay after link down
        -m MODE         API mode (mii, priv, ethtool, wlan, iff, auto)
        -k              Kill running daemon

ifup

ifup [-nmvf] [-i FILE] -a | IFACE...

        -a      Configure all interfaces
        -i FILE Use FILE instead of /etc/network/interfaces
        -n      Dry run
                (note: doesn't disable mappings)
        -m      Don't run any mappings
        -v      Print out what would happen before doing it
        -f      Force

init

init

Init is the first process started during boot. It never exits. It (re)spawns children according to /etc/inittab. Signals:

HUP: reload /etc/inittab TSTP: stop respawning until CONT QUIT: r-exec another init USR1/TERM/USR2/INT: run halt/reboot/poweroff/Ctrl-Alt-Del script

insmod

insmod FILE [SYMBOL=VALUE]...

Load kernel module

install

install [-cdDsp] [-o USER] [-g GRP] [-m MODE] [-t DIR] [SOURCE]... DEST

Copy files and set attributes

        -c      Just copy (default)
        -d      Create directories
        -D      Create leading target directories
        -s      Strip symbol table
        -p      Preserve date
        -o USER Set ownership
        -g GRP  Set group ownership
        -m MODE Set permissions
        -t DIR  Install to DIR

ionice

ionice [-c 1-3] [-n 0-7] [-p PID] [PROG ARGS]

Change I/O priority and class

        -c N    Class. 1:realtime 2:best-effort 3:idle
        -n N    Priority

iostat

iostat [-c] [-d] [-t] [-z] [-k|-m] [ALL|BLOCKDEV...] [INTERVAL [COUNT]]

Report CPU and I/O statistics

        -c      Show CPU utilization
        -d      Show device utilization
        -t      Print current time
        -z      Omit devices with no activity
        -k      Use kb/s
        -m      Use Mb/s

ip

OPTIONS := -f[amily] inet|inet6|link | -o[neline]

ipaddr

ipaddr add|del IFADDR dev IFACE | show|flush [dev IFACE] [to PREFIX]

ipcrm

ipcrm [-MQS key] [-mqs id]

Uppe-case options MQS remove an object by shmkey value. Lowe-case options remove an object by shmid value.

        -mM     Remove memory segment after last detach
        -qQ     Remove message queue
        -sS     Remove semaphore

ipcs

ipcs [[-smq] -i SHMID] | [[-asmq] [-tcplu]]

        -i ID   Show specific resource
Resource specification:

        -m      Shared memory segments
        -q      Message queues
        -s      Semaphore arrays
        -a      All (default)
Output format:

        -t      Time
        -c      Creator
        -p      Pid
        -l      Limits
        -u      Summary

iplink

ipneigh

ipneigh show|flush [to PREFIX] [dev DEV] [nud STATE]

iproute

iproute list|flush SELECTOR         SELECTOR := [root PREFIX] [match PREFIX] [proto RTPROTO]
        PREFIX := default|ADDR[/MASK]
iproute get ADDR [from ADDR iif IFACE]         [oif IFACE] [tos TOS]
iproute add|del|change|append|replace|test ROUTE         ROUTE := NODE_SPEC [INFO_SPEC]
        NODE_SPEC := PREFIX [table TABLE_ID] [proto RTPROTO] [scope SCOPE] [metric METRIC]
        INFO_SPEC := NH OPTIONS
        NH := [via [inet|inet6] ADDR] [dev IFACE] [src ADDR] [onlink]
        OPTIONS := [mtu [lock] NUM] [advmss [lock] NUM]

iprule

iprule [list] | add|del SELECTOR ACTION

        SELECTOR := [from PREFIX] [to PREFIX] [tos TOS] [fwmark FWMARK[/MASK]]
                        [dev IFACE] [pref NUMBER]
        ACTION := [table TABLE_ID] [nat ADDR]
                        [prohibit|reject|unreachable]
                        [realms [SRCREALM/]DSTREALM]
        TABLE_ID := [local|main|default|NUMBER]

iptunnel

kbd_mode

kbd_mode [-a|k|s|u] [-C TTY]

Report or set VT console keyboard mode

        -a      Default (ASCII)
        -k      Medium-raw (keycode)
        -s      Raw (scancode)
        -u      Unicode (utf-8)
        -C TTY  Affect TTY

kill

kill [-l] [-SIG] PID...

Send a signal (default: TERM) to given PIDs

        -l      List all signal names and numbers

killall

killall [-l] [-q] [-SIG] PROCESS_NAME...

Send a signal (default: TERM) to given processes

        -l      List all signal names and numbers
        -q      Don't complain if no processes were killed

killall5

killall5 [-l] [-SIG] [-o PID]...

Send a signal (default: TERM) to all processes outside current session

        -l      List all signal names and numbers
        -o PID  Don't signal this PID

last

last [-HW] [-f FILE]

Show listing of the last users that logged into the system

        -W      Display with no host column truncation
        -f FILE Read from FILE instead of /var/log/wtmp

less

less [-EFIMmNSRh~] [FILE]...

View FILE (or stdin) one screenful at a time

        -E      Quit once the end of a file is reached
        -F      Quit if entire file fits on first screen
        -I      Ignore case in all searches
        -M,-m   Display status line with line numbers
                and percentage through the file
        -N      Prefix line number to each line
        -S      Truncate long lines
        -R      Remove color escape codes in input
        -~      Suppress ~s displayed past EOF

link

link FILE LINK

Create hard LINK to FILE

ln

ln [-sfnbtv] [-S SUF] TARGET... LINK|DIR

Create a link LINK or DIR/TARGET to the specified TARGET(s)

        -s      Make symlinks instead of hardlinks
        -f      Remove existing destinations
        -n      Don't dereference symlinks - treat like normal file
        -b      Make a backup of the target (if exists) before link operation
        -S SUF  Use suffix instead of ~ when making backup files
        -T      Treat LINK as a file, not DIR
        -v      Verbose

loadfont

loadfont < font

Load a console font from stdin

loadkmap

loadkmap < keymap

Load a binary keyboard translation table from stdin

login

Begin a new session on the system

        -f      Don't authenticate (user already authenticated)
        -h HOST Host user came from (for network logins)
        -p      Preserve environment

logread

logread [-fF]

Show messages in syslogd's circular buffer

        -f      Output data as log grows
        -F      Same as -f, but dump buffer first

losetup

losetup [-rP] [-o OFS] {-f|LOOPDEV} FILE: associate loop devices         losetup -c LOOPDEV: reread file size
        losetup -d LOOPDEV: disassociate
        losetup -a: show status
        losetup -f: show next free loop device

        -o OFS  Start OFS bytes into FILE
        -P      Scan for partitions
        -r      Read-only
        -f      Show/use next free loop device

lpq

lpq [-P queue[@host[:port]]] [-U USERNAME] [-d JOBID]... [-fs]

        -P      lp service to connect to (else uses $PRINTER)
        -d      Delete jobs
        -f      Force any waiting job to be printed
        -s      Short display

lpr

lpr -P queue[@host[:port]] -U USERNAME -J TITLE -Vmh [FILE]...

        -P      lp service to connect to (else uses $PRINTER)
        -m      Send mail on completion
        -h      Print banner page too
        -V      Verbose

ls

ls [-1AaCxdLHRFplinshrSXvctu] [-w WIDTH] [FILE]...

List directory contents

        -1      One column output
        -a      Include entries which start with .
        -A      Like -a, but exclude . and ..
        -x      List by lines
        -d      List directory entries instead of contents
        -L      Follow symlinks
        -H      Follow symlinks on command line
        -R      Recurse
        -p      Append / to dir entries
        -F      Append indicator (one of */=@|) to entries
        -l      Long listing format
        -i      List inode numbers
        -n      List numeric UIDs and GIDs instead of names
        -s      List allocated blocks
        -lc     List ctime
        -lu     List atime
        --full-time     List full date and time
        -h      Human readable sizes (1K 243M 2G)
        --group-directories-first
        -S      Sort by size
        -X      Sort by extension
        -v      Sort by version
        -t      Sort by mtime
        -tc     Sort by ctime
        -tu     Sort by atime
        -r      Reverse sort order
        -w N    Format N columns wide
        --color[={always,never,auto}]   Control coloring

lsattr

lsattr [-Radlv] [FILE]...

List ext2 file attributes

        -R      Recurse
        -a      Don't hide entries starting with .
        -d      List directory entries instead of contents
        -l      List long flag names
        -v      List version/generation number

lsmod

lsmod

List loaded kernel modules

lsof

lsof

Show all open files

lspci

lspci [-mk]

List all PCI devices

        -m      Parsable output
        -k      Show driver

lzcat

lzcat [FILE]...

Decompress to stdout

lzma

lzma -d [-cfk] [FILE]...

Decompress FILEs (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force
        -k      Keep input files

lzop

lzop [-cfUvd123456789CF] [FILE]...

        -1..9   Compression level
        -d      Decompress
        -c      Write to stdout
        -f      Force
        -U      Delete input files
        -v      Verbose
        -F      Don't store or verify checksum
        -C      Also write checksum of compressed block

lzopcat

lzopcat [-vF] [FILE]...

        -v      Verbose
        -F      Don't verify checksum

makedevs

makedevs [-d device_table] rootdir

Create a range of special files as specified in a device table. Device table entries take the form of:

<name> <type> <mode> <uid> <gid> <major> <minor> <start> <inc> <count> Where name is the file name, type can be one of:         f       Regular file
        d       Directory
        c       Character device
        b       Block device
        p       Fifo (named pipe)
uid is the user id for the target file, gid is the group id for the target file. The rest of the entries (major, minor, etc) apply to to device special files. A '-' may be used for blank entries.

man

man [-aw] [SECTION] MANPAGE[.SECTION]...

Display manual page

        -a      Display all pages
        -w      Show page locations

$COLUMNS overrides output width

md5sum

md5sum [-c[sw]] [FILE]...

Print or check MD5 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

mdev

mdev [-vS] { [-s] | [-df] }

        -v      verbose
        -S      log to syslog too
        -s      scan /sys and populate /dev
        -d      daemon, listen on netlink
        -f      stay in foreground

Bare mdev is a kernel hotplug helper. To activate it: echo /sbin/mdev >/proc/sys/kernel/hotplug

It uses /etc/mdev.conf with lines [-][ENV=regex;]...DEVNAME UID:GID PERM [>|=PATH]|[!] [@|$|*PROG]
where DEVNAME is device name regex, @major,minor[-minor2], or environment variable regex. A common use of the latter is to load modules for hotplugged devices:

        $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"

If /dev/mdev.seq file exists, mdev will wait for its value to match $SEQNUM variable. This prevents plug/unplug races. To activate this feature, create empty /dev/mdev.seq at boot.

If /dev/mdev.log file exists, debug log will be appended to it.

mesg

mesg [y|n]

Control write access to your terminal y Allow write access to your terminal
n Disallow write access to your terminal

microcom

microcom [-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY

Copy bytes for stdin to TTY and from TTY to stdout

        -d      Wait up to DELAY ms for TTY output before sending every
                next byte to it
        -t      Exit if both stdin and TTY are silent for TIMEOUT ms
        -s      Set serial line to SPEED
        -X      Disable special meaning of NUL and Ctrl-X from stdin

mim

mim [-f FILE] [SHELL_OPTIONS] [TARGET] ...

Run a script from a Makefil-like specification file

        -f FILE         Spec file (default Mimfile)

minips

minips [-o COL1,COL2=HEADER] [-T]

Show list of processes

        -o COL1,COL2=HEADER     Select columns for display
        -T                      Show threads

mkdir

mkdir [-m MODE] [-p] DIRECTORY...

Create DIRECTORY

        -m MODE Mode
        -p      No error if exists; make parent directories as needed

mkdosfs

mkdosfs [-v] [-n LABEL] BLOCKDEV [KBYTES]

Make a FAT32 filesystem

        -v      Verbose
        -n LBL  Volume label

mke2fs

mke2fs [-Fn] [-b BLK_SIZE] [-i INODE_RATIO] [-I INODE_SIZE] [-m RESERVED_PERCENT] [-L LABEL] BLOCKDEV [KBYTES]

        -b BLK_SIZE     Block size, bytes
        -F              Force
        -i RATIO        Max number of files is filesystem_size / RATIO
        -I BYTES        Inode size (min 128)
        -L LBL          Volume label
        -m PERCENT      Percent of blocks to reserve for admin
        -n              Dry run

mkfifo

mkfifo [-m MODE] NAME

Create named pipe

        -m MODE Mode (default a=rw)

mkfs.ext2

mkfs.ext2 [-Fn] [-b BLK_SIZE] [-i INODE_RATIO] [-I INODE_SIZE] [-m RESERVED_PERCENT] [-L LABEL] BLOCKDEV [KBYTES]

        -b BLK_SIZE     Block size, bytes
        -F              Force
        -i RATIO        Max number of files is filesystem_size / RATIO
        -I BYTES        Inode size (min 128)
        -L LBL          Volume label
        -m PERCENT      Percent of blocks to reserve for admin
        -n              Dry run

mkfs.reiser

mkfs.reiser [-f] [-l LABEL] BLOCKDEV [4K-BLOCKS]

Make a ReiserFS V3 filesystem

        -f      Force
        -l LBL  Volume label

mkfs.vfat

mkfs.vfat [-v] [-n LABEL] BLOCKDEV [KBYTES]

Make a FAT32 filesystem

        -v      Verbose
        -n LBL  Volume label

mknod

mknod [-m MODE] NAME TYPE [MAJOR MINOR]

Create a special file (block, character, or pipe)

        -m MODE Creation mode (default a=rw)
TYPE:
        b       Block device
        c or u  Character device
        p       Named pipe (MAJOR MINOR must be omitted)

mkpasswd

mkpasswd [-s] [-p N] [-m TYPE] [-S SALT] [PASSWORD] [SALT]

Print crypt(3) hashed PASSWORD

        -P N    Read password from fd N
        -m TYPE des,md5,sha256/512 (default des)
        -S SALT

mkswap

mkswap [-L LBL] BLOCKDEV [KBYTES]

Prepare BLOCKDEV to be used as swap partition

        -L LBL  Label

mktemp

mktemp [-dt] [-p DIR] [TEMPLATE]

Create a temporary file with name based on TEMPLATE and print its name. TEMPLATE must end with XXXXXX (e.g. [/dir/]nameXXXXXX). Without TEMPLATE, -t tmp.XXXXXX is assumed.

        -d      Make directory, not file
        -q      Fail silently on errors
        -t      Prepend base directory name to TEMPLATE
        -p DIR  Use DIR as a base directory (implies -t)
        -u      Do not create anything; print a name

Base directory is: -p DIR, else $TMPDIR, else /tmp

modinfo

modinfo [-adlpn0] [-F keyword] MODULE

        -a              Shortcut for '-F author'
        -d              Shortcut for '-F description'
        -l              Shortcut for '-F license'
        -p              Shortcut for '-F parm'
        -F keyword      Keyword to look for
        -0              Separate output with NULs

modprobe

modprobe [-rq] MODULE [SYMBOL=VALUE]...

        -r      Remove MODULE
        -q      Quiet

more

more [FILE]...

View FILE (or stdin) one screenful at a time

mount

mount [OPTIONS] [-o OPT] DEVICE NODE

Mount a filesystem. Filesystem autodetection requires /proc.

        -a              Mount all filesystems in fstab
        -f              Update /etc/mtab, but don't mount
        -i              Don't run mount helper
        -n              Don't update /etc/mtab
        -v              Verbose
        -r              Read-only mount
        -t FSTYPE[,...] Filesystem type(s)
        -T FILE         Read FILE instead of /etc/fstab
        -O OPT          Mount only filesystems with option OPT (-a only)
-o OPT:
        loop            Ignored (loop devices are autodetected)
        [a]sync         Writes are [a]synchronous
        [no]atime       Disable/enable updates to inode access times
        [no]diratime    Disable/enable atime updates to directories
        [no]relatime    Disable/enable atime updates relative to modification time
        [no]dev         (Dis)allow use of special device files
        [no]exec        (Dis)allow use of executable files
        [no]suid        (Dis)allow set-user-id-root programs
        [r]shared       Convert [recursively] to a shared subtree
        [r]slave        Convert [recursively] to a slave subtree
        [r]private      Convert [recursively] to a private subtree
        [un]bindable    Make mount point [un]able to be bind mounted
        [r]bind         Bind a file or directory [recursively] to another location
        move            Relocate an existing mount point
        remount         Remount a mounted filesystem, changing flags
        ro              Same as -r

There are filesyste-specific -o flags.

mountpoint

mountpoint [-q] <[-dn] DIR | -x DEVICE>

Check if the directory is a mountpoint

        -q      Quiet
        -d      Print major/minor device number of the filesystem
        -n      Print device name of the filesystem
        -x      Print major/minor device number of the blockdevice

mpstat

mpstat [-A] [-I SUM|CPU|ALL|SCPU] [-u] [-P num|ALL] [INTERVAL [COUNT]]

Pe-processor statistics

        -A                      Same as -I ALL -u -P ALL
        -I SUM|CPU|ALL|SCPU     Report interrupt statistics
        -P num|ALL              Processor to monitor
        -u                      Report CPU utilization

mt

mt [-f DEVICE] OPCODE VALUE

Control magnetic tape drive operation

Available Opcodes:

bsf bsfm bsr bss datacompression drvbuffer eof eom erase fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2 ras3 reset retension rewind rewoffline seek setblk setdensity setpart tell unload unlock weof wset

mv

mv [-fin] SOURCE DEST or: mv [-fin] SOURCE... DIRECTORY

Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY

        -f      Don't prompt before overwriting
        -i      Interactive, prompt before overwrite
        -n      Don't overwrite an existing file

nameif

nameif [-s] [-c FILE] [IFNAME SELECTOR]...

Rename network interface while it in the down state. The device matched by SELECTOR is renamed to IFACE. SELECTOR can be a combination of:

        driver=STRING
        bus=STRING
        phy_address=NUM
        [mac=]XX:XX:XX:XX:XX:XX

        -c FILE Configuration file (default: /etc/mactab)
        -s      Log to syslog

nanddump

nanddump [-no] [--bb padbad|skipbad] [-s ADDR] [-l LEN] [-f FILE] MTD_DEVICE

Dump MTD_DEVICE

        -n      Read without ecc
        -o      Dump oob data
        -s ADDR Start address
        -l LEN  Length
        -f FILE Dump to file ('-' for stdout)
        --bb METHOD
                skipbad: skip bad blocks
                padbad: substitute bad blocks by 0xff (default)

nandwrite

nandwrite [-np] [-s ADDR] MTD_DEVICE [FILE]

Write to MTD_DEVICE

        -n      Write without ecc
        -p      Pad to page size
        -s ADDR Start address

nb-client

nb-client { [-b BLKSIZE] [-N NAME] [-t SEC] [-p] HOST [PORT] | -d } BLOCKDEV

Connect to HOST and provide network block device on BLOCKDEV

nc

nc [OPTIONS] HOST PORT - connect nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen

        -e PROG Run PROG after connect (must be last)
        -l      Listen mode, for inbound connects
        -lk     With -e, provides persistent server
        -p PORT Local port
        -s ADDR Local address
        -w SEC  Timeout for connects and final net reads
        -i SEC  Delay interval for lines sent
        -n      Don't do DNS resolution
        -u      UDP mode
        -b      Allow broadcasts
        -v      Verbose
        -o FILE Hex dump traffic
        -z      Zero-I/O mode (scanning)

netcat

netcat [OPTIONS] HOST PORT - connect nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen

        -e PROG Run PROG after connect (must be last)
        -l      Listen mode, for inbound connects
        -lk     With -e, provides persistent server
        -p PORT Local port
        -s ADDR Local address
        -w SEC  Timeout for connects and final net reads
        -i SEC  Delay interval for lines sent
        -n      Don't do DNS resolution
        -u      UDP mode
        -b      Allow broadcasts
        -v      Verbose
        -o FILE Hex dump traffic
        -z      Zero-I/O mode (scanning)

netstat

netstat [-ral] [-tuwx] [-enWp]

Display networking information

        -r      Routing table
        -a      All sockets
        -l      Listening sockets
                Else: connected sockets
        -t      TCP sockets
        -u      UDP sockets
        -w      Raw sockets
        -x      Unix sockets
                Else: all socket types
        -e      Other/more information
        -n      Don't resolve names
        -W      Wide display
        -p      Show PID/program name for sockets

nice

nice [-n ADJUST] [PROG ARGS]

Change scheduling priority, run PROG

        -n ADJUST       Adjust priority by ADJUST

nl

nl [OPTIONS] [FILE]...

Write FILEs to standard output with line numbers added

        -b STYLE        Which lines to number - a: all, t: nonempty, n: none
        -i N            Line number increment
        -s STRING       Use STRING as line number separator
        -v N            Start from N
        -w N            Width of line numbers

nmeter

nmeter [-d MSEC] FORMAT_STRING

Monitor system in real time

 -d MSEC        Milliseconds between updates, default:1000, none:-1

Format specifiers:

 %Nc or %[cN]   CPU. N - bar size (default 10)
                (displays: S:system U:user N:niced D:iowait I:irq i:softirq)
 %[nINTERFACE]  Network INTERFACE
 %m             Allocated memory
 %[mf]          Free memory
 %[mt]          Total memory
 %s             Allocated swap
 %f             Number of used file descriptors
 %Ni            Total/specific IRQ rate
 %x             Context switch rate
 %p             Forks
 %[pn]          # of processes
 %b             Block io
 %Nt            Time (with N decimal points)
 %NT            Zero-based timestamp (with N decimal points)
 %r             Print <cr> instead of <lf> at EOL

nohup

nohup PROG ARGS

Run PROG immune to hangups, with output to a no-tty

nologin

nologin

Politely refuse a login

nproc

nproc --all --ignore=N

Print number of available CPUs

        --all           Number of installed CPUs
        --ignore=N      Exclude N CPUs

nsenter

nsenter [OPTIONS] [PROG ARGS]

        -t PID          Target process to get namespaces from
        -m[FILE]        Enter mount namespace
        -u[FILE]        Enter UTS namespace (hostname etc)
        -i[FILE]        Enter System V IPC namespace
        -n[FILE]        Enter network namespace
        -p[FILE]        Enter pid namespace
        -U[FILE]        Enter user namespace
        -S UID          Set uid in entered namespace
        -G GID          Set gid in entered namespace
        --preserve-credentials  Don't touch uids or gids
        -r[DIR]         Set root directory
        -w[DIR]         Set working directory
        -F              Don't fork before exec'ing PROG

nslookup

nslookup [-type=QUERY_TYPE] [-debug] HOST [DNS_SERVER]

Query DNS about HOST

QUERY_TYPE: soa,ns,a,aaaa,cname,mx,txt,ptr,any

ntpd

ntpd [-dnqNwl] [-I IFACE] [-S PROG] [-k KEYFILE] [-p [keyno:N:]PEER]...

NTP client/server

        -d[d]   Verbose
        -n      Do not daemonize
        -q      Quit after clock is set
        -N      Run at high priority
        -w      Do not set time (only query peers), implies -n
        -S PROG Run PROG after stepping time, stratum change, and every 11 min
        -k FILE Key file (ntp.keys compatible)
        -p [keyno:NUM:]PEER
                Obtain time from PEER (may be repeated)
                Use key NUM for authentication
                If -p is not given, 'server HOST' lines
                from /etc/ntp.conf are used
        -l      Also run as server on port 123
        -I IFACE Bind server to IFACE, implies -l

nuke

nuke DIR...

Remove DIRs

openvt

openvt [-c N] [-sw] [PROG ARGS]

Start PROG on a new virtual terminal

        -c N    Use specified VT
        -s      Switch to the VT
        -w      Wait for PROG to exit

partprobe

partprobe DEVICE...

Ask kernel to rescan partition table

passwd

passwd [-a ALG] [-dlu] [USER]

Change USER's password (default: current user)

        -a ALG  des,md5,sha256/512 (default des)
        -d      Set password to ''
        -l      Lock (disable) account
        -u      Unlock (enable) account

paste

paste [-d LIST] [-s] [FILE]...

Paste lines from each input file, separated with tab

        -d LIST Use delimiters from LIST, not tab
        -s      Serial: one file at a time

patch

patch [-RNE] [-p N] [-i DIFF] [ORIGFILE [PATCHFILE]]

        -p N    Strip N leading components from file names
        -i DIFF Read DIFF instead of stdin
        -R      Reverse patch
        -N      Ignore already applied patches
        -E      Remove output files if they become empty
        --dry-run       Don't actually change files

pgrep

pgrep [-flanovx] [-s SID|-P PPID|PATTERN]

Display process(es) selected by regex PATTERN

        -l      Show command name too
        -a      Show command line too
        -f      Match against entire command line
        -n      Show the newest process only
        -o      Show the oldest process only
        -v      Negate the match
        -x      Match whole name (not substring)
        -s      Match session ID (0 for current)
        -P      Match parent process ID

pidof

pidof [-s] [-o PID] [NAME]...

List PIDs of all processes with names that match NAMEs

        -s      Show only one PID
        -o PID  Omit given pid
                Use %PPID to omit pid of pidof's parent

ping

ping [OPTIONS] HOST

Send ICMP ECHO_REQUESTs to HOST

        -4,-6           Force IP or IPv6 name resolution
        -c CNT          Send only CNT pings
        -s SIZE         Send SIZE data bytes in packets (default 56)
        -i SECS         Interval
        -A              Ping as soon as reply is recevied
        -t TTL          Set TTL
        -I IFACE/IP     Source interface or IP address
        -W SEC          Seconds to wait for the first response (default 10)
                        (after all -c CNT packets are sent)
        -w SEC          Seconds until ping exits (default:infinite)
                        (can exit earlier with -c CNT)
        -q              Quiet, only display output at start/finish
        -p HEXBYTE      Payload pattern

ping6

ping6 [OPTIONS] HOST

Send ICMP ECHO_REQUESTs to HOST

        -c CNT          Send only CNT pings
        -s SIZE         Send SIZE data bytes in packets (default 56)
        -i SECS         Interval
        -A              Ping as soon as reply is recevied
        -I IFACE/IP     Source interface or IP address
        -W SEC          Seconds to wait for the first response (default 10)
                        (after all -c CNT packets are sent)
        -w SEC          Seconds until ping exits (default:infinite)
                        (can exit earlier with -c CNT)
        -q              Quiet, only display output at start/finish
        -p HEXBYTE      Payload pattern

pivot_root

pivot_root NEW_ROOT PUT_OLD

Move the current root file system to PUT_OLD and make NEW_ROOT the new root file system

pkill

pkill [-l|-SIGNAL] [-fnovx] [-s SID|-P PPID|PATTERN]

Send a signal to process(es) selected by regex PATTERN

        -l      List all signals
        -f      Match against entire command line
        -n      Signal the newest process only
        -o      Signal the oldest process only
        -v      Negate the match
        -x      Match whole name (not substring)
        -s      Match session ID (0 for current)
        -P      Match parent process ID

pmap

pmap [-xq] PID...

Display process memory usage

        -x      Show details
        -q      Quiet

popmaildir

popmaildir [OPTIONS] MAILDIR [CONN_HELPER ARGS]

Fetch content of remote mailbox to local maildir

        -s              Skip authorization
        -T              Get messages with TOP instead of RETR
        -k              Keep retrieved messages on the server
        -t SEC          Network timeout
        -F 'PROG ARGS'  Filter program (may be repeated)
        -M 'PROG ARGS'  Delivery program

Fetch from plain POP3 server: popmaildir -k DIR nc pop3.server.com 110 <user_and_pass.txt Fetch from SSLed POP3 server and delete fetched emails: popmaildir DIR - openssl s_client -quiet -connect pop3.server.com:995 <user_and_pass.txt

poweroff

poweroff [-d DELAY] [-nf]

Halt and shut off power

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)

powertop

powertop

Analyze power consumption on Inte-based laptops

printenv

printenv [VARIABLE]...

Print environment VARIABLEs. If no VARIABLE specified, print all.

printf

printf FORMAT [ARG]...

Format and print ARG(s) according to FORMAT (a-la C printf)

ps

ps [-o COL1,COL2=HEADER] [-T]

Show list of processes

        -o COL1,COL2=HEADER     Select columns for display
        -T                      Show threads

pscan

pscan [-cb] [-p MIN_PORT] [-P MAX_PORT] [-t TIMEOUT] [-T MIN_RTT] HOST

Scan HOST, print all open ports

        -c      Show closed ports too
        -b      Show blocked ports too
        -p PORT Scan from this port (default 1)
        -P PORT Scan up to this port (default 1024)
        -t MS   Timeout (default 5000 ms)
        -T MS   Minimum rtt (default 5 ms)

pstree

pstree [-p] [PID|USER]

Display process tree, optionally start from USER or PID

        -p      Show pids

pwd

pwd

Print the full filename of the current working directory

pwdx

pwdx PID...

Show current directory for PIDs

raidautorun

raidautorun DEVICE

Tell the kernel to automatically search and start RAID arrays

rdate

rdate [-s/-p] HOST

Set and print time from HOST using RFC 868

        -s      Only set system time
        -p      Only print time

readahead

readahead [FILE]...

Preload FILEs to RAM

readlink

readlink [-fnv] FILE

Display the value of a symlink

        -f      Canonicalize by following all symlinks
        -n      Don't add newline
        -v      Verbose

realpath

realpath FILE...

Return the absolute pathnames of given FILE

reboot

reboot [-d DELAY] [-nf]

Reboot the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)

renice

renice [-n] PRIORITY [[-p | -g | -u] ID...]...

Change scheduling priority of a running process

        -n      Add PRIORITY to current nice value
                Without -n, nice value is set to PRIORITY
        -p      Process ids (default)
        -g      Process group ids
        -u      Process user names

reset

reset

Reset the screen

resize

resize

Resize the screen

resume

resume BLOCKDEV [OFFSET]

Restore system state from 'suspend-to-disk' data in BLOCKDEV

rev

rev [FILE]...

Reverse lines of FILE

rm

rm [-irf] FILE...

Remove (unlink) FILEs

        -i      Always prompt before removing
        -f      Never prompt
        -R,-r   Recurse

rmdir

rmdir [-p] DIRECTORY...

Remove DIRECTORY if it is empty

        -p      Include parents
        --ignore-fail-on-non-empty

rmmod

rmmod MODULE...

Unload kernel modules

route

route [-ne] [-A inet[6]] [{add|del} [-net|-host] TARGET [netmask MASK] [gw GATEWAY] [metric N] [mss BYTES] [window BYTES] [reject] [IFACE]]

Show or edit kernel routing tables

        -n      Don't resolve names
        -e      Display other/more information
        -A inet[6]      Select address family

rtcwake

rtcwake [-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]

Enter a system sleep state until specified wakeup time

        -a      Read clock mode from /var/lib/hwclock/adjtime (default)
        -l      Clock is set to local time
        -u      Clock is set to UTC time
        -d DEV  Specify the RTC device
        -m MODE Set sleep state (default: standby)
        -s SEC  Set timeout in SEC seconds from now
        -t TIME Set timeout to TIME seconds from epoch

ru-init

ru-init [-d CAP,CAP...] [-n] [-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]

Free initramfs and switch to another root fs:

chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /, execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.

        -c DEV  Reopen stdio to DEV after switch
        -d CAPS Drop capabilities
        -n      Dry run

runlevel

runlevel [FILE]

Find the current and previous system runlevel

If no utmp FILE exists or if no runlevel record can be found, print ``unknown''

rx

rx FILE

Receive a file using the xmodem protocol

script

script [-afq] [-t[FILE]] [-c PROG] [OUTFILE]

Default OUTFILE is 'typescript'

        -a      Append output
        -c PROG Run PROG, not shell
        -q      Quiet
        -t[FILE] Send timing to stderr or FILE

scriptreplay

scriptreplay TIMINGFILE [TYPESCRIPT [DIVISOR]]

Play back typescripts, using timing information

sed

sed [-i[SFX]] [-nrE] [-f FILE]... [-e CMD]... [FILE]... or: sed [-i[SFX]] [-nrE] CMD [FILE]...

        -e CMD  Add CMD to sed commands to be executed
        -f FILE Add FILE contents to sed commands to be executed
        -i[SFX] Edit files in-place (otherwise sends to stdout)
                Optionally back files up, appending SFX
        -n      Suppress automatic printing of pattern space
        -r,-E   Use extended regex syntax

If no -e or -f, the first no-option argument is the sed command string. Remaining arguments are input files (stdin if none).

sendmail

sendmail [-tv] [-f SENDER] [-amLOGIN 4<user_pass.txt | -auUSER -apPASS] [-w SECS] [-H 'PROG ARGS' | -S HOST] [RECIPIENT_EMAIL]...

Read email from stdin and send it

Standard options:

        -t              Read additional recipients from message body
        -f SENDER       For use in MAIL FROM:<sender>. Can be empty string
                        Default: -auUSER, or username of current UID
        -o OPTIONS      Various options. -oi implied, others are ignored
        -i              -oi synonym, implied and ignored

Busybox specific options:

        -v              Verbose
        -w SECS         Network timeout
        -H 'PROG ARGS'  Run connection helper. Examples:
                openssl s_client -quiet -tls1 -starttls smtp -connect smtp.gmail.com:25
                openssl s_client -quiet -tls1 -connect smtp.gmail.com:465
                        $SMTP_ANTISPAM_DELAY: seconds to wait after helper connect
        -S HOST[:PORT]  Server (default $SMTPHOST or 127.0.0.1)
        -amLOGIN        Log in using AUTH LOGIN
        -amPLAIN        or AUTH PLAIN
                        (-amCRAM-MD5 not supported)
        -auUSER         Username for AUTH
        -apPASS         Password for AUTH

If no -a options are given, authentication is not done. If -amLOGIN is given but no -au/-ap, user/password is read from fd #4. Other options are silently ignored; -oi is implied.

seq

seq [-w] [-s SEP] [FIRST [INC]] LAST

Print numbers from FIRST to LAST, in steps of INC. FIRST, INC default to 1.

        -w      Pad to last with leading zeros
        -s SEP  String separator

setarch

setarch PERSONALITY [-R] PROG ARGS

PERSONALITY may be:

        linux32 Set 32bit uname emulation
        linux64 Set 64bit uname emulation

        -R      Disable address space randomization

setconsole

setconsole [-r] [DEVICE]

Make writes to /dev/console appear on DEVICE (default: /dev/tty). Does not redirect kernel log output or reads from /dev/console.

        -r      Reset: writes to /dev/console go to kernel log tty(s)

setfattr

setfattr [-h] -n|-x ATTR [-v VALUE] FILE...

Set extended attributes

        -h              Do not follow symlinks
        -x ATTR         Remove attribute ATTR
        -n ATTR         Set attribute ATTR to VALUE
        -v VALUE        (default: empty)

setfont

setfont FONT [-m MAPFILE] [-C TTY]

Load a console font

        -m MAPFILE      Load console screen map
        -C TTY          Affect TTY instead of /dev/tty

setkeycodes

setkeycodes { SCANCODE KEYCODE }...

Modify kernel's scancod-t-keycode map, allowing unusual keyboards to generate usable keycodes.

SCANCODE is either xx or e0xx (hexadecimal), KEYCODE is decimal.

setlogcons

setlogcons [N]

Pin kernel output to VT console N. Default:0 (do not pin)

setpriv

setpriv [OPTIONS] PROG ARGS

Run PROG with different privilege settings

-d,--dump            Show current capabilities
--nnp,--no-new-privs    Ignore setuid/setgid bits and file capabilities
--inh-caps CAP,CAP      Set inheritable capabilities
--ambient-caps CAP,CAP  Set ambient capabilities

setserial

setserial [-abGvz] { DEVICE [PARAMETER [ARG]]... | -g DEVICE... }

Print or set serial port parameters

        -a      Print all
        -b      Print summary
        -G      Print as setserial PARAMETERs
        -v      Verbose
        -z      Zero out serial flags before setting
        -g      All args are device names

PARAMETERs: (* = takes ARG, ^ = can be turned off by preceding ^)         *port, *irq, *divisor, *uart, *baud_base, *close_delay, *closing_wait,
        ^fourport, ^auto_irq, ^skip_test, ^sak, ^session_lockout, ^pgrp_lockout,
        ^callout_nohup, ^split_termios, ^hup_notify, ^low_latency, autoconfig,
        spd_normal, spd_hi, spd_vhi, spd_shi, spd_warp, spd_cust
ARG for uart:

        unknown, 8250, 16450, 16550, 16550A, Cirrus, 16650, 16650V2, 16750,
        16950, 16954, 16654, 16850, RSA, NS16550A, XSCALE, RM9000, OCTEON, AR7,
        U6_16550A

setsid

setsid [-c] PROG ARGS

Run PROG in a new session. PROG will have no controlling terminal and will not be affected by keyboard signals (^C etc).

        -c      Set controlling terminal to stdin

setuidgid

setuidgid USER PROG ARGS

Set uid and gid to USER's uid and gid, drop supplementary group ids, run PROG

sh

sh [-/+OPTIONS] [-/+o OPT]... [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS] / -s [ARGS]]

Unix shell interpreter

sha1sum

sha1sum [-c[sw]] [FILE]...

Print or check SHA1 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha256sum

sha256sum [-c[sw]] [FILE]...

Print or check SHA256 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha3sum

sha3sum [-c[sw]] [-a BITS] [FILE]...

Print or check SHA3 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines
        -a BITS 224 (default), 256, 384, 512

sha512sum

sha512sum [-c[sw]] [FILE]...

Print or check SHA512 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

showkey

showkey [-a | -k | -s]

Show keys pressed

        -a      Display decimal/octal/hex values of the keys
        -k      Display interpreted keycodes (default)
        -s      Display raw scan-codes

shred

shred FILE...

Overwrite/delete FILEs

        -f      Chmod to ensure writability
        -n N    Overwrite N times (default 3)
        -z      Final overwrite with zeros
        -u      Remove file

shuf

shuf [-e|-i L-H] [-n NUM] [-o FILE] [-z] [FILE|ARG...]

Randomly permute lines

        -e      Treat ARGs as lines
        -i L-H  Treat numbers L-H as lines
        -n NUM  Output at most NUM lines
        -o FILE Write to FILE, not standard output
        -z      End lines with zero byte, not newline

sleep

sleep [N]...

Pause for a time equal to the total of the args given, where each arg can have an optional suffix of (s)econds, (m)inutes, (h)ours, or (d)ays

softlimit

softlimit [-a BYTES] [-m BYTES] [-d BYTES] [-s BYTES] [-l BYTES] [-f BYTES] [-c BYTES] [-r BYTES] [-o N] [-p N] [-t N]
PROG ARGS

Set soft resource limits, then run PROG

        -a BYTES        Limit total size of all segments
        -m BYTES        Same as -d BYTES -s BYTES -l BYTES -a BYTES
        -d BYTES        Limit data segment
        -s BYTES        Limit stack segment
        -l BYTES        Limit locked memory size
        -o N            Limit number of open files per process
        -p N            Limit number of processes per uid
Options controlling file sizes:

        -f BYTES        Limit output file sizes
        -c BYTES        Limit core file size
Efficiency opts:

        -r BYTES        Limit resident set size
        -t N            Limit CPU time, process receives
                        a SIGXCPU after N seconds

sort

sort [-nrugMcszbdfiokt] [-o FILE] [-k START[.OFS][OPTS][,END[.OFS][OPTS]] [-t CHAR] [FILE]...

Sort lines of text

        -o FILE Output to FILE
        -c      Check whether input is sorted
        -b      Ignore leading blanks
        -f      Ignore case
        -i      Ignore unprintable characters
        -d      Dictionary order (blank or alphanumeric only)
        -n      Sort numbers
        -g      General numerical sort
        -M      Sort month
        -V      Sort version
        -t CHAR Field separator
        -k N[,M] Sort by Nth field
        -r      Reverse sort order
        -s      Stable (don't sort ties alphabetically)
        -u      Suppress duplicate lines
        -z      Lines are terminated by NUL, not newline

split

split [OPTIONS] [INPUT [PREFIX]]

        -b N[k|m]       Split by N (kilo|mega)bytes
        -l N            Split by N lines
        -a N            Use N letters as suffix

ssl_client

ssl_client [-e] -s FD [-r FD] [-n SNI]

star-sto-daemon

star-sto-daemon [OPTIONS] [-S|-K] ... [-- ARGS...]

Search for matching processes, and then -K: stop all matching processes -S: start a process unless a matching process is found

Process matching:

        -u USERNAME|UID Match only this user's processes
        -n NAME         Match processes with NAME
                        in comm field in /proc/PID/stat
        -x EXECUTABLE   Match processes with this command
                        in /proc/PID/cmdline
        -p FILE         Match a process with PID from FILE
        All specified conditions must match
-S only:
        -x EXECUTABLE   Program to run
        -a NAME         Zeroth argument
        -b              Background
        -N N            Change nice level
        -c USER[:[GRP]] Change user/group
        -m              Write PID to pidfile specified by -p
-K only:
        -s SIG          Signal to send
        -t              Match only, exit with 0 if found
Other:

        -o              Exit with status 0 if nothing is done
        -v              Verbose
        -q              Quiet

stat

stat [-ltf] [-c FMT] FILE...

Display file (default) or filesystem status

        -c FMT  Use the specified format
        -f      Display filesystem status
        -L      Follow links
        -t      Terse display

FMT sequences for files:

 %a     Access rights in octal
 %A     Access rights in human readable form
 %b     Number of blocks allocated (see %B)
 %B     Size in bytes of each block reported by %b
 %d     Device number in decimal
 %D     Device number in hex
 %f     Raw mode in hex
 %F     File type
 %g     Group ID
 %G     Group name
 %h     Number of hard links
 %i     Inode number
 %n     File name
 %N     File name, with -> TARGET if symlink
 %o     I/O block size
 %s     Total size in bytes
 %t     Major device type in hex
 %T     Minor device type in hex
 %u     User ID
 %U     User name
 %x     Time of last access
 %X     Time of last access as seconds since Epoch
 %y     Time of last modification
 %Y     Time of last modification as seconds since Epoch
 %z     Time of last change
 %Z     Time of last change as seconds since Epoch

FMT sequences for file systems:

 %a     Free blocks available to non-superuser
 %b     Total data blocks
 %c     Total file nodes
 %d     Free file nodes
 %f     Free blocks
 %i     File System ID in hex
 %l     Maximum length of filenames
 %n     File name
 %s     Block size (for faster transfer)
 %S     Fundamental block size (for block counts)
 %t     Type in hex
 %T     Type in human readable form

strings

strings [-fo] [-t o/d/x] [-n LEN] [FILE]...

Display printable strings in a binary file

        -f              Precede strings with filenames
        -o              Precede strings with octal offsets
        -t o/d/x        Precede strings with offsets in base 8/10/16
        -n LEN          At least LEN characters form a string (default 4)

stty

stty [-a|g] [-F DEVICE] [SETTING]...

Without arguments, prints baud rate, line discipline, and deviations from stty sane

        -F DEVICE       Open device instead of stdin
        -a              Print all current settings in human-readable form
        -g              Print in stty-readable form
        [SETTING]       See manpage

su

su [-lmp] [-] [-s SH] [USER [SCRIPT ARGS / -c 'CMD' ARG0 ARGS]]

Run shell under USER (by default, root)

        -,-l    Clear environment, go to home dir, run shell as login shell
        -p,-m   Do not set new $HOME, $SHELL, $USER, $LOGNAME
        -c CMD  Command to pass to 'sh -c'
        -s SH   Shell to use instead of user's default

sum

sum [-rs] [FILE]...

Checksum and count the blocks in a file

        -r      Use BSD sum algorithm (1K blocks)
        -s      Use System V sum algorithm (512byte blocks)

svc

svc [-udopchaitkx] SERVICE_DIR...

Control services monitored by runsv supervisor

        -u      If service is not running, start it; restart if it stops
        -d      If service is running, send TERM+CONT signals; do not restart it
        -o      Once: if service is not running, start it; do not restart it
        -pchaitk Send STOP, CONT, HUP, ALRM, INT, TERM, KILL signal to service
        -x      Exit: runsv will exit as soon as the service is down

svok

svok SERVICE_DIR

Check whether runsv supervisor is running. Exit code is 0 if it does, 100 if it does not, 111 (with error message) if SERVICE_DIR does not exist.

swapoff

swapoff [-a] [DEVICE]

Stop swapping on DEVICE

        -a      Stop swapping on all swap devices

swapon

swapon [-a] [-e] [-d[POL]] [-p PRI] [DEVICE]

Start swapping on DEVICE

        -a      Start swapping on all swap devices
        -d[POL] Discard blocks at swapon (POL=once),
                as freed (POL=pages), or both (POL omitted)
        -e      Silently skip devices that do not exist
        -p PRI  Set swap device priority

switch_root

switch_root [-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]

Free initramfs and switch to another root fs:

chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /, execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.

        -c DEV  Reopen stdio to DEV after switch

sync

sync [-df] [FILE]...

Write all buffered blocks (in FILEs) to disk -d Avoid syncing metadata
-f Sync filesystems underlying FILEs

sysctl

sysctl -p [-enq] [FILE...] / [-enqaw] [KEY[=VALUE]]...

Show/set kernel parameters

        -p      Set values from FILEs (default /etc/sysctl.conf)
        -e      Don't warn about unknown keys
        -n      Don't show key names
        -q      Quiet
        -a      Show all values
        -w      Set values

tac

tac [FILE]...

Concatenate FILEs and print them in reverse

tail

tail [OPTIONS] [FILE]...

Print last 10 lines of each FILE (or stdin) to stdout. With more than one FILE, precede each with a filename header.

        -f              Print data as file grows
        -c [+]N[kbm]    Print last N bytes
        -n N[kbm]       Print last N lines
        -n +N[kbm]      Start on Nth line and print the rest
        -q              Never print headers
        -s SECONDS      Wait SECONDS between reads with -f
        -v              Always print headers
        -F              Same as -f, but keep retrying

N may be suffixed by k (x1024), b (x512), or m (x1024^2).

tar

tar c|x|t [-ZzJjahmvokO] [-f TARFILE] [-C DIR] [-T FILE] [-X FILE] [OPTION]... [FILE]...

Create, extract, or list files from a tar file

        c       Create
        x       Extract
        t       List
        -f FILE Name of TARFILE ('-' for stdin/out)
        -C DIR  Change to DIR before operation
        -v      Verbose
        -O      Extract to stdout
        -m      Don't restore mtime
        -o      Don't restore user:group
        -k      Don't replace existing files
        -Z      (De)compress using compress
        -z      (De)compress using gzip
        -J      (De)compress using xz
        -j      (De)compress using bzip2
        --lzma  (De)compress using lzma
        -a      (De)compress based on extension
        -h      Follow symlinks
        -T FILE File with names to include
        -X FILE File with glob patterns to exclude
        --exclude PATTERN       Glob pattern to exclude
        --overwrite             Replace existing files
        --strip-components NUM  NUM of leading components to strip
        --no-recursion          Don't descend in directories
        --numeric-owner         Use numeric user:group
        --no-same-permissions   Don't restore access permissions
        --to-command COMMAND    Pipe files to COMMAND

tc

tc OBJECT CMD [dev STRING]

tee

tee [-ai] [FILE]...

Copy stdin to each FILE, and also to stdout

        -a      Append to the given FILEs, don't overwrite
        -i      Ignore interrupt signals (SIGINT)

telnet

telnet [-a] [-l USER] HOST [PORT]

Connect to telnet server

        -a      Automatic login with $USER variable
        -l USER Automatic login as USER

telnetd

telnetd [OPTIONS]

Handle incoming telnet connections

        -l LOGIN        Exec LOGIN on connect
        -f ISSUE_FILE   Display ISSUE_FILE instead of /etc/issue
        -K              Close connection as soon as login exits
                        (normally wait until all programs close slave pty)
        -p PORT         Port to listen on
        -b ADDR[:PORT]  Address to bind to
        -F              Run in foreground
        -i              Inetd mode
        -w SEC          Inetd 'wait' mode, linger time SEC
        -S              Log to syslog (implied by -i or without -F and -w)

tftp

tftp [OPTIONS] HOST [PORT]

Transfer a file from/to tftp server

        -l FILE Local FILE
        -r FILE Remote FILE
        -g      Get file
        -p      Put file
        -b SIZE Transfer blocks in bytes

tftpd

tftpd [-crl] [-u USER] [DIR]

Transfer a file on tftp client's request

tftpd should be used as an inetd service. tftpd's line for inetd.conf: 69 dgram udp nowait root tftpd tftpd -l /files/to/serve
It also can be ran from udpsvd:

        udpsvd -vE 0.0.0.0 69 tftpd /files/to/serve

        -r      Prohibit upload
        -c      Allow file creation via upload
        -u USER Access files as USER
        -l      Log to syslog (inetd mode requires this)

time

time [-vpa] [-o FILE] PROG ARGS

Run PROG, display resource usage when it exits

        -v      Verbose
        -p      POSIX output format
        -f FMT  Custom format
        -o FILE Write result to FILE
        -a      Append (else overwrite)

timeout

timeout [-s SIG] SECS PROG ARGS

Run PROG. Send SIG to it if it is not gone in SECS seconds. Default SIG: TERM.

top

top [-bmH] [-n COUNT] [-d SECONDS]

Provide a view of process activity in real time. Read the status of all processes from /proc each SECONDS and display a screenful of them. Keys:

        N/M/P/T: show CPU usage, sort by pid/mem/cpu/time
        S: show memory
        R: reverse sort
        H: toggle threads, 1: toggle SMP
        Q,^C: exit
Options:

        -b      Batch mode
        -n N    Exit after N iterations
        -d SEC  Delay between updates
        -m      Same as 's' key
        -H      Show threads

touch

touch [-c] [-d DATE] [-t DATE] [-r FILE] FILE...

Update the las-modified date on the given FILE[s]

        -c      Don't create files
        -h      Don't follow links
        -d DT   Date/time to use
        -t DT   Date/time to use
        -r FILE Use FILE's date/time

tr

tr [-cds] STRING1 [STRING2]

Translate, squeeze, or delete characters from stdin, writing to stdout

        -c      Take complement of STRING1
        -d      Delete input characters coded STRING1
        -s      Squeeze multiple output characters of STRING2 into one character

traceroute

traceroute [-46IFlnrv] [-f 1ST_TTL] [-m MAXTTL] [-q PROBES] [-p PORT] [-t TOS] [-w WAIT_SEC] [-s SRC_IP] [-i IFACE]
[-z PAUSE_MSEC] HOST [BYTES]

Trace the route to HOST

        -4,-6   Force IP or IPv6 name resolution
        -F      Set don't fragment bit
        -I      Use ICMP ECHO instead of UDP datagrams
        -l      Display TTL value of the returned packet
        -n      Print numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -f N    First number of hops (default 1)
        -m N    Max number of hops
        -q N    Number of probes per hop (default 3)
        -p N    Base UDP port number used in probes
                (default 33434)
        -s IP   Source address
        -i IFACE Source interface
        -t N    Type-of-service in probe packets (default 0)
        -w SEC  Wait for a response (default 3)
        -z MSEC Wait before each send

traceroute6

traceroute6 [-Inrv] [-f 1ST_TTL] [-m MAXTTL] [-q PROBES] [-p PORT] [-t TOS] [-w WAIT_SEC] [-s SRC_IP] [-i IFACE]
[-z PAUSE_MSEC] HOST [BYTES]

Trace the route to HOST

        -I      Use ICMP ECHO instead of UDP datagrams
        -n      Print numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -f N    First number of hops (default 1)
        -m N    Max number of hops
        -q N    Number of probes per hop (default 3)
        -p N    Base UDP port number used in probes
                (default 33434)
        -s IP   Source address
        -i IFACE Source interface
        -t N    Type-of-service in probe packets (default 0)
        -w SEC  Wait for a response (default 3)
        -z MSEC Wait before each send

truncate

truncate [-c] -s SIZE FILE...

Truncate FILEs to the given size

        -c      Do not create files
        -s SIZE Truncate to SIZE

ts

ts [-is] [STRFTIME]

tty

tty

Print file name of stdin's terminal

        -s      Print nothing, only return exit status

ttysize

ttysize [w] [h]

Print dimensions of stdin tty, or 80x24

tunctl

tunctl [-f DEVICE] [-t NAME | -d NAME] [-u USER] [-g GRP] [-b]

Create or delete TUN/TAP interfaces

        -f DEV  TUN device (default /dev/net/tun)
        -t NAME Create iface (default: tapN)
        -d NAME Delete iface
        -u USER Set iface owner
        -g GRP  Set iface group
        -b      Brief output

tune2fs

tune2fs [-c MAX_MOUNT_COUNT] [-i DAYS] [-C MOUNT_COUNT] [-L LABEL] BLOCKDEV

Adjust filesystem options on ext[23] filesystems

ubiattach

ubiattach -m MTD_NUM [-d UBI_NUM] [-O VID_HDR_OFF] UBI_CTRL_DEV

Attach MTD device to UBI

        -m MTD_NUM      MTD device number to attach
        -d UBI_NUM      UBI device number to assign
        -O VID_HDR_OFF  VID header offset

ubidetach

ubidetach -d UBI_NUM UBI_CTRL_DEV

Detach MTD device from UBI

        -d UBI_NUM      UBI device number

ubimkvol

ubimkvol -N NAME [-s SIZE | -m] UBI_DEVICE

Create UBI volume

        -a ALIGNMENT    Volume alignment (default 1)
        -m              Set volume size to maximum available
        -n VOLID        Volume ID. If not specified,
                        assigned automatically
        -N NAME         Volume name
        -s SIZE         Size in bytes
        -t TYPE         Volume type (static|dynamic)

ubirename

ubirename UBI_DEVICE OLD_VOLNAME NEW_VOLNAME [OLD2 NEW2]...

Rename UBI volumes on UBI_DEVICE

ubirmvol

ubirmvol -n VOLID / -N VOLNAME UBI_DEVICE

Remove UBI volume

        -n VOLID        Volume ID
        -N VOLNAME      Volume name

ubirsvol

ubirsvol -n VOLID -s SIZE UBI_DEVICE

Resize UBI volume

        -n VOLID        Volume ID
        -s SIZE         Size in bytes

ubiupdatevol

ubiupdatevol -t UBI_DEVICE | [-s SIZE] UBI_DEVICE IMG_FILE

Update UBI volume

        -t      Truncate to zero size
        -s SIZE Size in bytes to resize to

udhcpc

udhcpc [-fbqvRB] [-a[MSEC]] [-t N] [-T SEC] [-A SEC/-n] [-i IFACE] [-P PORT] [-s PROG] [-p PIDFILE]
[-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]...

        -i IFACE        Interface to use (default eth0)
        -P PORT         Use PORT (default 68)
        -s PROG         Run PROG at DHCP events (default /usr/share/udhcpc/default.script)
        -p FILE         Create pidfile
        -B              Request broadcast replies
        -t N            Send up to N discover packets (default 3)
        -T SEC          Pause between packets (default 3)
        -A SEC          Wait if lease is not obtained (default 20)
        -b              Background if lease is not obtained
        -n              Exit if lease is not obtained
        -q              Exit after obtaining lease
        -R              Release IP on exit
        -f              Run in foreground
        -S              Log to syslog too
        -a[MSEC]        Validate offered address with ARP ping
        -r IP           Request this IP address
        -o              Don't request any options (unless -O is given)
        -O OPT          Request option OPT from server (cumulative)
        -x OPT:VAL      Include option OPT in sent packets (cumulative)
                        Examples of string, numeric, and hex byte opts:
                        -x hostname:bbox - option 12
                        -x lease:3600 - option 51 (lease time)
                        -x 0x3d:0100BEEFC0FFEE - option 61 (client id)
                        -x 14:'"dumpfile"' - option 14 (shell-quoted)
        -F NAME         Ask server to update DNS mapping for NAME
        -V VENDOR       Vendor identifier (default 'udhcp VERSION')
        -C              Don't send MAC as client identifier
        -v              Verbose
Signals:

        USR1    Renew lease
        USR2    Release lease

udhcpc6

udhcpc6 [-fbnqvodR] [-i IFACE] [-r IPv6] [-s PROG] [-p PIDFILE] [-x OPT:VAL]... [-O OPT]... [-P PORT]

        -i IFACE        Interface to use (default eth0)
        -p FILE         Create pidfile
        -s PROG         Run PROG at DHCP events (default /usr/share/udhcpc/default.script)
        -B              Request broadcast replies
        -t N            Send up to N discover packets
        -T N            Pause between packets (default 3 seconds)
        -A N            Wait N seconds (default 20) after failure
        -f              Run in foreground
        -b              Background if lease is not obtained
        -n              Exit if lease is not obtained
        -q              Exit after obtaining lease
        -R              Release IP on exit
        -S              Log to syslog too
        -P PORT         Use PORT (default 546)
        -O OPT          Request option OPT from server (cumulative)
        -o              Don't request any options (unless -O is given)
        -r IPv6         Request this address ('no' to not request any IP)
        -d              Request prefix
        -l              Send 'information request' instead of 'solicit'
                        (used for servers which do not assign IPv6 addresses)
        -x OPT:VAL      Include option OPT in sent packets (cumulative)
                        Examples of string, numeric, and hex byte opts:
                        -x hostname:bbox - option 12
                        -x lease:3600 - option 51 (lease time)
                        -x 0x3d:0100BEEFC0FFEE - option 61 (client id)
                        -x 14:'"dumpfile"' - option 14 (shell-quoted)
        -v              Verbose
Signals:

        USR1    Renew lease
        USR2    Release lease

udhcpd

udhcpd [-fS] [-I ADDR] [-P PORT] [CONFFILE]

DHCP server

        -f      Run in foreground
        -S      Log to syslog too
        -I ADDR Local address
        -a MSEC Timeout for ARP ping (default 2000)
        -P PORT Use PORT (default 67)
Signals:

        USR1    Update lease file

uevent

uevent [PROG ARGS]

uevent runs PROG for every netlink notification. PROG's environment contains data passed from the kernel. Typical usage (daemon for dynamic device node creation): # uevent mdev & mdev -s

umount

umount [-rlfmda] [-t FSTYPE] FILESYSTEM|DIRECTORY

Unmount filesystems

        -a      Unmount all filesystems in /etc/mtab
        -n      Don't erase /etc/mtab entries
        -r      Remount devices read-only if mount is busy
        -l      Lazy umount (detach filesystem)
        -f      Force umount (i.e., unreachable NFS server)
        -d      Free loop device if it has been used
        -t FSTYPE[,...] Unmount only these filesystem type(s)

uname

uname [-amnrspvio]

Print system information

        -a      Print all
        -m      The machine (hardware) type
        -n      Hostname
        -r      Kernel release
        -s      Kernel name (default)
        -p      Processor type
        -v      Kernel version
        -i      The hardware platform
        -o      OS name

uncompress

uncompress [-cf] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Overwrite

unexpand

unexpand [-fa][-t N] [FILE]...

Convert spaces to tabs, writing to stdout

        -a      Convert all blanks
        -f      Convert only leading blanks
        -t N    Tabstops every N chars

uniq

uniq [-cdui] [-f,s,w N] [INPUT [OUTPUT]]

Discard duplicate lines

        -c      Prefix lines by the number of occurrences
        -d      Only print duplicate lines
        -u      Only print unique lines
        -i      Ignore case
        -f N    Skip first N fields
        -s N    Skip first N chars (after any skipped fields)
        -w N    Compare N characters in line

unit

unit

Run the uni-test suite

unix2dos

unix2dos [-ud] [FILE]

Convert FILE i-place from Unix to DOS format. When no file is given, use stdin/stdout.

        -u      dos2unix
        -d      unix2dos

unlink

unlink FILE

Delete FILE by calling unlink()

unlzma

unlzma [-cfk] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -k      Keep input files

unlzop

unlzop [-cfUvF] [FILE]...

        -c      Write to stdout
        -f      Force
        -U      Delete input files
        -v      Verbose
        -F      Don't verify checksum

unshare

unshare [OPTIONS] [PROG ARGS]

        -m,--mount[=FILE]       Unshare mount namespace
        -u,--uts[=FILE]         Unshare UTS namespace (hostname etc.)
        -i,--ipc[=FILE]         Unshare System V IPC namespace
        -n,--net[=FILE]         Unshare network namespace
        -p,--pid[=FILE]         Unshare PID namespace
        -U,--user[=FILE]        Unshare user namespace
        -f                      Fork before execing PROG
        -r                      Map current user to root (implies -U)
        --mount-proc[=DIR]      Mount /proc filesystem first (implies -m)
        --propagation slave|shared|private|unchanged
                                Modify mount propagation in mount namespace
        --setgroups allow|deny  Control the setgroups syscall in user namespaces

unxz

unxz [-cfk] [FILE]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -k      Keep input files
        -t      Test file integrity

unzip

unzip [-lnojpq] FILE[.zip] [FILE]... [-x FILE...] [-d DIR]

Extract FILEs from ZIP archive

        -l      List contents (with -q for short form)
        -n      Never overwrite files (default: ask)
        -o      Overwrite
        -j      Do not restore paths
        -p      Print to stdout
        -q      Quiet
        -x FILE Exclude FILEs
        -d DIR  Extract into DIR

uptime

uptime

Display the time since the last boot

users

users

Print the users currently logged on

usleep

usleep N

Pause for N microseconds

vconfig

vconfig COMMAND [OPTIONS]

Create and remove virtual ethernet devices

        add             IFACE VLAN_ID
        rem             VLAN_NAME
        set_flag        IFACE 0|1 VLAN_QOS
        set_egress_map  VLAN_NAME SKB_PRIO VLAN_QOS
        set_ingress_map VLAN_NAME SKB_PRIO VLAN_QOS
        set_name_type   NAME_TYPE

vi

vi [-c CMD] [-R] [FILE]...

Edit FILE

        -c CMD  Initial command to run ($EXINIT also available)
        -R      Read-only
        -H      List available features

vlock

vlock [-a]

Lock a virtual terminal. A password is required to unlock.

        -a      Lock all VTs

volname

volname [DEVICE]

Show CD volume name of the DEVICE (default /dev/cdrom)

w

Show who is logged on

wall

wall [FILE]

Write content of FILE or stdin to all logge-in users

watch

watch [-n SEC] [-t] PROG ARGS

Run PROG periodically

        -n SEC  Loop period (default 2)
        -t      Don't print header

watchdog

watchdog [-t N[ms]] [-T N[ms]] [-F] DEV

Periodically write to watchdog device DEV

        -T N    Reboot after N seconds if not reset (default 60)
        -t N    Reset every N seconds (default 30)
        -F      Run in foreground

Use 500ms to specify period in milliseconds

wc

wc [-cmlwL] [FILE]...

Count lines, words, and bytes for each FILE (or stdin)

        -c      Count bytes
        -m      Count characters
        -l      Count newlines
        -w      Count words
        -L      Print longest line length

wget

wget [-cqS] [--spider] [-O FILE] [-o LOGFILE] [--header 'HEADER: VALUE'] [-Y on/off] [--no-check-certificate] [-P DIR] [-U AGENT] [-T SEC] URL...

Retrieve files via HTTP or FTP

        --spider        Only check URL existence: $? is 0 if exists
        --no-check-certificate  Don't validate the server's certificate
        -c              Continue retrieval of aborted transfer
        -q              Quiet
        -P DIR          Save to DIR (default .)
        -S              Show server response
        -T SEC          Network read timeout is SEC seconds
        -O FILE         Save to FILE ('-' for stdout)
        -o LOGFILE      Log messages to FILE
        -U STR          Use STR for User-Agent header
        -Y on/off       Use proxy

which

which COMMAND...

Locate COMMAND

who

who [-a]

Show who is logged on

        -a      Show all
        -H      Print column headers

whoami

whoami

Print the user name associated with the current effective user id

whois

whois [-i] [-h SERVER] [-p PORT] NAME...

Query WHOIS info about NAME

        -i      Show redirect results too
        -h,-p   Server to query

xargs

xargs [OPTIONS] [PROG ARGS]

Run PROG on every item given by stdin

        -0      Input is separated by NULs
        -a FILE Read from FILE instead of stdin
        -r      Don't run command if input is empty
        -t      Print the command on stderr before execution
        -p      Ask user whether to run each command
        -E STR,-e[STR]  STR stops input processing
        -I STR  Replace STR within PROG ARGS with input line
        -n N    Pass no more than N args to PROG
        -s N    Pass command line of no more than N bytes
        -P N    Run up to N PROGs in parallel
        -x      Exit if size is exceeded

xxd

xxd [-pr] [-g N] [-c N] [-n LEN] [-s OFS] [FILE]

Hex dump FILE (or stdin)

        -g N            Bytes per group
        -c N            Bytes per line
        -p              Show only hex bytes, assumes -c30
        -l LENGTH       Show only first LENGTH bytes
        -s OFFSET       Skip OFFSET bytes
        -r              Reverse (with -p, assumes no offsets in input)

xz

xz -d [-cfk] [FILE]...

Decompress FILEs (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force
        -k      Keep input files
        -t      Test file integrity

xzcat

xzcat [FILE]...

Decompress to stdout

yes

yes [STRING]

Repeatedly output a line with STRING, or 'y'

zcat

zcat [FILE]...

Decompress to stdout

zcip

zcip [OPTIONS] IFACE SCRIPT

Manage a ZeroConf IPv4 lin-local address

        -f              Run in foreground
        -q              Quit after obtaining address
        -r 169.254.x.x  Request this address first
        -l x.x.0.0      Use this range instead of 169.254
        -v              Verbose

$LOGGING=none Suppress logging
$LOGGING=syslog Log to syslog

With no -q, runs continuously monitoring for ARP conflicts, exits only on I/O errors (link down etc)

LIBC NSS

GNU Libc (glibc) uses the Name Service Switch (NSS) to configure the behavior of the C library for the local environment, and to configure how it reads system data, such as passwords and group information. This is implemented using an /etc/nsswitch.conf configuration file, and using one or more of the /lib/libnss_* libraries. BusyBox tries to avoid using any libc calls that make use of NSS. Some applets however, such as login and su, will use libc functions that require NSS.

If you enable CONFIG_USE_BB_PWD_GRP, BusyBox will use internal functions to directly access the /etc/passwd, /etc/group, and /etc/shadow files without using NSS. This may allow you to run your system without the need for installing any of the NSS configuration files and libraries.

When used with glibc, the BusyBox 'networking' applets will similarly require that you install at least some of the glibc NSS stuff (in particular, /etc/nsswitch.conf, /lib/libnss_dns*, /lib/libnss_files*, and /lib/libresolv*).

Shameless Plug: As an alternative, one could use a C library such as uClibc. In addition to making your system significantly smaller, uClibc does not require the use of any NSS support files or libraries.

MAINTAINER

Denis Vlasenko <vda.linux@googlemail.com>

AUTHORS

The following people have contributed code to BusyBox whether they know it or not. If you have written code included in BusyBox, you should probably be listed here so you can obtain your bit of eternal glory. If you should be listed here, or the description of what you have done needs more detail, or is incorrect, please send in an update.

Emanuele Aina <emanuele.aina@tiscali.it>
ru-parts

Erik Andersen <andersen@codepoet.org>

    Tons of new stuff, major rewrite of most of the
    core apps, tons of new apps as noted in header files.
    Lots of tedious effort writing these boring docs that
    nobody is going to actually read.

Laurence Anderson <l.d.anderson@warwick.ac.uk>

    rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm

Jeff Angielski <jeff@theptrgroup.com>

    ftpput, ftpget

Edward Betts <edward@debian.org>

    expr, hostid, logname, whoami

John Beppu <beppu@codepoet.org>

    du, nslookup, sort

Brian Candler <B.Candler@pobox.com>

    tiny-ls(ls)

Randolph Chung <tausq@debian.org>

    fbset, ping, hostname

Dave Cinege <dcinege@psychosis.com>

    more(v2), makedevs, dutmp, modularization, auto links file,
    various fixes, Linux Router Project maintenance

Jordan Crouse <jordan@cosmicpenguin.net>

    ipcalc

Magnus Damm <damm@opensource.se>

    tftp client insmod powerpc support

Larry Doolittle <ldoolitt@recycle.lbl.gov>

    pristine source directory compilation, lots of patches and fixes.

Glenn Engel <glenne@engel.org>

    httpd

Gennady Feldman <gfeldman@gena01.com>

    Sysklogd (single threaded syslogd, IPC Circular buffer support,
    logread), various fixes.

Karl M. Hegbloom <karlheg@debian.org>

    cp_mv.c, the test suite, various fixes to utility.c, &c.

Daniel Jacobowitz <dan@debian.org>

    mktemp.c

Matt Kraai <kraai@alumni.cmu.edu>

    documentation, bugfixes, test suite

Stephan Linz <linz@li-pro.net>

    ipcalc, Red Hat equivalence

John Lombardo <john@deltanet.com>

tr

Glenn McGrath <bug1@iinet.net.au>

    Common unarchiving code and unarchiving applets, ifupdown, ftpgetput,
    nameif, sed, patch, fold, install, uudecode.
    Various bugfixes, review and apply numerous patches.

Manuel Novoa III <mjn3@codepoet.org>

    cat, head, mkfifo, mknod, rmdir, sleep, tee, tty, uniq, usleep, wc, yes,
    mesg, vconfig, make_directory, parse_mode, dirname, mode_string,
    get_last_path_component, simplify_path, and a number trivial libbb routines

    also bug fixes, partial rewrites, and size optimizations in
    ash, basename, cal, cmp, cp, df, du, echo, env, ln, logname, md5sum, mkdir,
    mv, realpath, rm, sort, tail, touch, uname, watch, arith, human_readable,
    interface, dutmp, ifconfig, route

Vladimir Oleynik <dzo@simtreas.ru>

    cmdedit; xargs(current), httpd(current);
    ports: ash, crond, fdisk, inetd, stty, traceroute, top;
    locale, various fixes
    and irreconcilable critic of everything not perfect.

Bruce Perens <bruce@pixar.com>

    Original author of BusyBox in 1995, 1996. Some of his code can
    still be found hiding here and there...

Tim Riker <Tim@Rikers.org>

    bug fixes, member of fan club

Kent Robotti <robotti@metconnect.com>

    reset, tons and tons of bug reports and patches.

Chip Rosenthal <chip@unicom.com>, <crosenth@covad.com>

    wget - Contributed by permission of Covad Communications

Pavel Roskin <proski@gnu.org>

    Lots of bugs fixes and patches.

Gyepi Sam <gyepi@praxis-sw.com>

    Remote logging feature for syslogd

Linus Torvalds <torvalds@transmeta.com>

    mkswap, fsck.minix, mkfs.minix

Mark Whitley <markw@codepoet.org>

    grep, sed, cut, xargs(previous),
    style-guide, new-applet-HOWTO, bug fixes, etc.

Charles P. Wright <cpwright@villagenet.com>

    gzip, mini-netcat(nc)

Enrique Zanardi <ezanardi@ull.es>

    tarcat (since removed), loadkmap, various fixes, Debian maintenance

Tito Ragusa <farmatito@tiscali.it>

    devfsd and size optimizations in strings, openvt and deallocvt.

Paul Fox <pgf@foxharp.boston.ma.us>

    vi editing mode for ash, various other patches/fixes

Roberto A. Foglietta <me@roberto.foglietta.name>

    port: dnsd

Bernhard Reutne-Fischer <rep.dot.nop@gmail.com>

    misc

Mike Frysinger <vapier@gentoo.org>

    initial e2fsprogs, printenv, setarch, sum, misc

Jie Zhang <jie.zhang@analog.com>

    fixed two bugs in msh and hush (exitcode of killed processes)