coreutils: truncate invocation
14.5 ‘truncate’: Shrink or extend the size of a file
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‘truncate’ shrinks or extends the size of each FILE to the specified
size. Synopsis:
truncate OPTION... FILE...
Any FILE 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 (or
hole) reads as zero bytes.
The program accepts the following options. Also see ⇒Common
options.
‘-c’
‘--no-create’
Do not create files that do not exist.
‘-o’
‘--io-blocks’
Treat SIZE as number of I/O blocks of the FILE rather than bytes.
‘-r RFILE’
‘--reference=RFILE’
Base the size of each FILE on the size of RFILE.
‘-s SIZE’
‘--size=SIZE’
Set or adjust the size of each FILE according to SIZE. SIZE is in
bytes unless ‘--io-blocks’ is specified. SIZE may be, or may be an
integer optionally followed by, one of the following multiplicative
suffixes:
‘KB’ => 1000 (KiloBytes)
‘K’ => 1024 (KibiBytes)
‘MB’ => 1000*1000 (MegaBytes)
‘M’ => 1024*1024 (MebiBytes)
‘GB’ => 1000*1000*1000 (GigaBytes)
‘G’ => 1024*1024*1024 (GibiBytes)
and so on for ‘T’, ‘P’, ‘E’, ‘Z’, and ‘Y’. Binary prefixes can be
used, too: ‘KiB’=‘K’, ‘MiB’=‘M’, and so on.
SIZE may also be prefixed by one of the following to adjust the
size of each FILE based on its current size:
‘+’ => extend by
‘-’ => reduce by
‘<’ => at most
‘>’ => at least
‘/’ => round down to multiple of
‘%’ => round up to multiple of
An exit status of zero indicates success, and a nonzero value
indicates failure.