truncate Man page

TRUNCATE(1) User Commands TRUNCATE(1)


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


truncate OPTION… FILE…


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 extended part (hole) reads
as zero bytes.

Mandatory arguments to long options are mandatory for short options

-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

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 (powers of 1024) or KB,MB,…
(powers of 1000).

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.


Written by Padraig Brady.


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Copyright © 2016 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


dd, truncate, ftruncate

Full documentation at:
or available locally via: info ‘(coreutils) truncate invocation’

GNU coreutils 8.25 February 2016 TRUNCATE(1)