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 ‘-’. Synopsis:
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
The program accepts the following options. Also see Common 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.
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 (see
next section) is preferable in new applications.
An exit status of zero indicates success, and a nonzero value indicates failure.