php man page for truncate

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 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 (powers of 1024) or KB,MB,... (pow-
       ers 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.

AUTHOR
       Written by Padraig Brady.

REPORTING BUGS
       GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
       Report truncate translation bugs to <http://translationproject.org/team/>

COPYRIGHT
       Copyright (C) 2017 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3 or later <http://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 at: <http://www.gnu.org/software/coreutils/truncate>
       or available locally via: info '(coreutils) truncate invocation'

GNU coreutils 8.28						   January 2018 						       TRUNCATE(1)