truncate - shrink or extend the size of a file to the specified size - man(1) - [phpMan]

Che Dong

Shrink or extend the size of a file to the specified size.

Set a size of 10 GB to an existing file, or create a new file with the specified size
truncate {{-s|--size}} 10G {{path/to/file}}
Extend the file size by 50 MiB, fill with holes (which reads as zero bytes)
truncate {{-s|--size}} +50M {{path/to/file}}
Shrink the file by 2 GiB, by removing data from the end of file
truncate {{-s|--size}} -2G {{path/to/file}}
Empty the file's content
truncate {{-s|--size}} 0 {{path/to/file}}
Empty the file's content, but do not create the file if it does not exist
truncate {{-s|--size}} 0 {{-c|--no-create}} {{path/to/file}}

TRUNCATE(1)                                 User Commands                                TRUNCATE(1)

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.

       -c, --no-create
              do not create any files

       -o, --io-blocks
              treat SIZE as number of IO blocks instead of bytes

       -r, --reference=RFILE
              base size on RFILE

       -s, --size=SIZE
              set or adjust the file size by SIZE bytes

       --help display this help and exit

       --version
              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
       GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
       Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT
       Copyright  ©  2023 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.

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

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

GNU coreutils 9.4                           January 2026                                 TRUNCATE(1)

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man > truncate(1)