TRUNCATE

Section: User Commands (1)
Updated: February 2026
Index Return to Main Contents

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NAME

truncate - shrink or extend the size of a file to the specified size  

SYNOPSIS

truncate ,OPTION/... ,FILE/...  

DESCRIPTION

Shrink or extend the size of each FILE to the specified size

A FILE argument that does not exist is created.

If a FILE is larger than the specified size, the extra data is lost. If a FILE is shorter, it is extended and the sparse extended part (hole) reads as zero bytes.

Mandatory arguments to long options are mandatory for short options too.

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#truncat-c'-c, --no-createX'tty: link'

do not create any files

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#truncat-o'-o, --io-blocksX'tty: link'

treat SIZE as number of IO blocks instead of bytes

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#truncat-r'-r, --reference=,RFILEX'tty: link'/

base size on RFILE

X'tty: link https://www.gnu.org/software/coreutils/manual/coreutils.html#truncat-s'-s, --size=,SIZEX'tty: link'/

set or adjust the file size by SIZE bytes

X'tty: link https://www.gnu.org/software/coreutils/truncate#truncat-help'--helpX'tty: link'

display this help and exit

X'tty: link https://www.gnu.org/software/coreutils/truncate#truncat-version'--versionX'tty: link'

output version information and exit

The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y,R,Q (powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

SIZE may also be prefixed by one of the following modifying characters: '+' extend by, '-' reduce by, '<' at most, '>' at least, '/' round down to multiple of, '%' round up to multiple of.  

AUTHOR

Written by Padraig Brady.  

REPORTING BUGS

Report bugs to: bug-coreutils@gnu.org

Report Gentoo bugs to: https://bugs.gentoo.org/
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Report any translation bugs to <https://translationproject.org/team/>  

SEE ALSO

dd(1), truncate(2), ftruncate(2)

Full documentation <https://www.gnu.org/software/coreutils/truncate>
or available locally via: info aq(coreutils) truncate invocationaq

Packaged by Gentoo (9.10 (p0))
Copyright © 2026 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

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Index

NAME

SYNOPSIS

DESCRIPTION

AUTHOR

REPORTING BUGS

SEE ALSO