php man page for sum

SUM(1)								   User Commands							    SUM(1)

NAME

       sum - checksum and count the blocks in a file

SYNOPSIS

       sum [OPTION]... [FILE]...

DESCRIPTION

       Print checksum and block counts for each FILE.

       With no FILE, or when FILE is -, read standard input.

       -r     use BSD sum algorithm, use 1K blocks

       -s, --sysv
	      use System V sum algorithm, use 512 bytes blocks

       --help display this help and exit

       --version
	      output version information and exit

AUTHOR

       Written by Kayvan Aghaiepour and David MacKenzie.

REPORTING BUGS

       GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
       Report sum 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

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

GNU coreutils 8.28						   January 2018 							    SUM(1)