File: coreutils.info,  Node: truncate invocation,  Prev: sync invocation,  Up: File space usage

14.5 ‘truncate’: Shrink or extend the size of a file
====================================================

‘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 *note 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’, ‘Y’, ‘R’, and ‘Q’.  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.