‘sum’: Print checksum and block counts
‘sum’ computes a 16-bit checksum for each given FILE, or standard input if none are given or for a FILE of ‘-‘.
sum [OPTION]… [FILE]…
‘sum’ prints the checksum for each FILE followed by the number of blocks in the file (rounded up). If more than one FILE is given, file names are also printed (by default). (With the ‘–sysv’ option, corresponding file names are printed when there is at least one file argument.)
By default, GNU ‘sum’ computes checksums using an algorithm compatible with BSD ‘sum’ and prints file sizes in units of 1024-byte blocks.
The program accepts the following options.
Use the default (BSD compatible) algorithm. This option is included for compatibility with the System V ‘sum’. Unless ‘-s’ was also given, it has no effect.
‘-s’ | ‘–sysv’
Compute checksums using an algorithm compatible with System V ‘sum”s default, and print file sizes in units of 512-byte blocks.
‘sum’ is provided for compatibility; the ‘cksum’ program is preferable in new applications.
An exit status of zero indicates success, and a nonzero value indicates failure.