www.LinuxHowtos.org

This is a list of some handy/common things you can do on the command line in Linux.

Commands

lynx -dump -width=999 http://www.linuxhowtos.org/Misc/commandline.htm >cmd.txt

Make a text copy of this page

apropos word

show commands pertinent to word

which command

show full path name of command

time command

see how long a command takes

nice command

run a low priority command

renice 19 -p $$

make shell (script) low priority. Useful for non interactive tasks

look prefix

quickly search dictionary

grep --color word /usr/share/dict/words

highlight occurances of words in dictionary

gpg -c file

encrypt file

gpg file.gpg

decrypt file

echo 'wget url' | at 01:00

download url at 1AM to current dir

echo "mail -s 'get the train' you@yourdomain < /dev/null" | at 17:45

email reminder

watch -n1 'cat /proc/interrupts'

watch changeable data continuously

alias hd='od -Ax -tx1z -v'

handy hexdump. (usage e.g.: hd /proc/self/cmdline | less)

disc space

ls /usr/bin | pr -T9 -W$COLUMNS

print in 9 columns to width of terminal

touch -c -t 0304050607 file

set file timestamp (YYMMDDhhmm)

pstree -hlp

show process hierarchy

lsof /dir/file

show process using file

ls -lSr

show files, biggest last

du -sh file dir

show disk usage of file and dir. See also dutop

df -h

free disk space

df -i

free inodes

fdisk -l

show disks partitions sizes (run as root)

rpm -q -a --queryformat '%10{SIZE} %{NAME}' | sort -k1,1n

list all packages by size

Dir navigation

cd -

go to previous directory

cd ~

go to home directory

(cd dir && command)

go to dir, execute command and return to current dir

pushd .

put current dir on stack so you can popd back to it

CDs

gzip < /dev/cdrom > cdrom.iso.gz

save copy of data cdrom

mkisofs -r dir | gzip > cdrom.iso.gz

create cdrom image from directory

mount -oloop cdrom.iso /mnt/dir

mount the cdrom image at /mnt/dir (for browsing)

gzip -dc cdrom.iso.gz | cdrecord dev=/dev/cdrom -

burn cdrom image (use dev=ATAPI -scanbus to confirm dev)

cdparanoia -B

rip audio tracks from CD to wav files in current dir

cdrecord dev=/dev/cdrom -audio *.wav

make audio CD from all wavs in current dir

oggenc --tracknum='track' track.cdda.wav -o 'track.ogg'

make ogg file from wav file

rsync (Use the --dry-run option for testing)

rsync -P rsync://rsync.server.com/path/to/file file

Only get diffs. Do multiple times for troublesome downloads

rsync --bwlimit=1000 fromfile tofile

Locally copy with rate limit. It's like nice for I/O

rsync -az -e ssh --delete ~/public_html/ remote.com:'~/public_html'

Mirror web site (using compressed rsync over encrypted ssh)

rsync -auz -e ssh remote:/dir/ . && rsync -auz -e ssh . remote:/dir/

Synchronize current directory with remote one

file searching

alias l='ls -l --color=auto'

quick dir listing

ls -lrt

list files by date. See also newest

find -name '*.[ch]' | xargs grep -E 'search string'

search *.c and *.h for 'search string' in this dir and below

find -type f -print0 | xargs -r0 grep -E 'search string'

search all regular files for 'search string' in this dir and below

find -type f -maxdepth 1 | xargs grep -E 'search string'

search all regular files for 'search string' in this dir

find -type f ! -perm -444

find files not readable by all (useful for web site)

find -type d ! -perm -111

find dirs not accessible by all (useful for web site)

locate -r 'file[^/]*.txt'

search cached index for names. This re is like glob *file*.txt

Networking

(Note ifconfig, route, mii-tool, nslookup commands are obsolete)

ip link show

list interfaces

ethtool interface

list interface status

ip link set dev eth0 name wan

rename eth0 to wan

ip addr add 1.2.3.4/24 brd + dev eth0

add ip and mask(255.255.255.0)

ip link set dev interface up

bring interface up (or down)

ip route add default via 1.2.3.254

set default gateway to 1.2.3.254

host google.com

lookup ip address for name or vice versa

netstat -lp --inet

list internet services on a system

netstat -p --inet

list active connections to/from system

echo 'message' | smbclient -M netbiosname

Send popup to windows machine (off by default as of XP sp2)

Math

echo '(1 + sqrt(5))/2' | bc -l

quick math

echo 'obase=16; ibase=10; 123' | bc

base conversion (decimal to hex)

echo 'pad=20; min=64; (100*10^6)/((pad+min)*8)' | bc

More complex (integer) e.g. This shows max FastE packet rate

echo 'pad=20; min=64; print (100E6)/((pad+min)*8)' | python

python handles scientific notation

echo 'pad=20; plot [64:1518] (100*10**6)/((pad+x)*8)' | gnuplot -persist

Plot FastE packet rate vs packet size

text manipulation

(note these use stdin and stdout, so if you want to edit files, append < oldfile > newfile)

sed 's/string1/string2/g'

replace string1 with string2

sed '/ *#/d; /^ *$/d'

remove comments and blank lines

sed ':a; /\$/N; s/\//; ta'

concatenate lines with trailing

sed 's/[ ]*$//'

remove trailing spaces from lines

sed 's/([\`\"$\\])/\1/g'

backslashify shell metacharacters active within double-quotes

sort file1 file1 file2 | uniq -u

show lines in file2 not in file1

echo 'Test' | tr '[:lower:]' '[:upper:]'

case conversion

tr -dc '[:print:]' < /dev/urandom

filter non printable characters

grep 'processor' /proc/cpuinfo | wc -l

count lines

Calendar

cal -3

display a calendar

date --date='25 Dec' +%A

what day does xmas fall on, this year

date --date '1970-01-01 UTC 1097781420 seconds'

convert number of seconds since the epoch to a date

TZ=':America/Los_Angeles' date

What time is it on West coast of US (use tzselect to find TZ)

locales

printf "%'d" 1234

print number with thousands grouping appropriate to locale

echo "I live in `locale territory`"

extract info from locale database

locale | cut -d= -f1 | xargs locale -kc | less

list fields in locale database

LANG=ga_IE locale int_prefix

lookup locale info for specific country. See also ccodes

recode

(Obsoletes iconv, dos2unix, unix2dos)

recode -l | less

show available conversions (aliases on each line)

recode windows-1252.. file_to_change.txt

windows "ansi" to local charset (auto does CRLF conversion)

recode utf-8/CRLF.. file_to_change.txt

windows utf8 to local charset

recode iso-8859-15..utf8 file_to_change.txt

latin9 (western europe) to utf8

recode ../b64 < file.txt > file.b64

Base64 encode

recode ..HTML < file.txt > file.html

text to HTML

recode -lf windows-1252

show table of characters

echo -n 0xA4 | recode latin-9/x1..dump

show what the character is in charmap

echo -n 0x20AC | recode ucs-2/x2..1252/x

show windows-1252 encoding

echo -n 0x20AC | recode ucs-2/x2..utf-8/x

show utf-8 encoding

interactive

mc

powerful filemanager that can browse rpm, tar, ftp, ssh, ...

screen

virtual terminals with detach capability, ...

lynx

web browser

gnuplot

interactive/scriptable graphing

octave

matlab like environment

From http://www.iol.ie/~padraiga/cmdline.html

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