NAME

       shasum - Print or Check SHA Checksums

SYNOPSIS

        Usage: shasum [OPTION]... [FILE]...
        Print or check SHA checksums.
        With no FILE, or when FILE is -, read standard input.

          -a, --algorithm   1 (default), 224, 256, 384, 512, 512224, 512256
          -b, --binary      read in binary mode
          -c, --check       read SHA sums from the FILEs and check them
          -t, --text        read in text mode (default)
          -p, --portable    read in portable mode
                                produces same digest on Windows/Unix/Mac
          -0, --01          read in BITS mode
                                ASCII '0' interpreted as 0-bit,
                                ASCII '1' interpreted as 1-bit,
                                all other characters ignored

        The following two options are useful only when verifying checksums:
          -s, --status      don't output anything, status code shows success
          -w, --warn        warn about improperly formatted checksum lines

          -h, --help        display this help and exit
          -v, --version     output version information and exit

        When verifying SHA-512/224 or SHA-512/256 checksums, indicate the
        algorithm explicitly using the -a option, e.g.

          shasum -a 512224 -c checksumfile

        The sums are computed as described in FIPS-180-4.  When checking, the
        input should be a former output of this program.  The default mode is to
        print a line with checksum, a character indicating type (`*' for binary,
        ` ' for text, `?' for portable, `^' for BITS), and name for each FILE.

        Report shasum bugs to mshelor@cpan.org

DESCRIPTION

       Running shasum is often the quickest way to compute SHA message digests.  The user simply
       feeds data to the script through files or standard input, and then collects the results
       from standard output.

       The following command shows how to compute digests for typical inputs such as the NIST
       test vector "abc":

               perl -e "print qq(abc)" | shasum

       Or, if you want to use SHA-256 instead of the default SHA-1, simply say:

               perl -e "print qq(abc)" | shasum -a 256

       Since shasum mimics the behavior of the combined GNU sha1sum, sha224sum, sha256sum,
       sha384sum, and sha512sum programs, you can install this script as a convenient drop-in
       replacement.

       Unlike the GNU programs, shasum encompasses the full SHA standard by allowing partial-byte
       inputs.  This is accomplished through the BITS option (-0).  The following example
       computes the SHA-224 digest of the 7-bit message 0001100:

               perl -e "print qq(0001100)" | shasum -0 -a 224

AUTHOR

       Copyright (c) 2003-2013 Mark Shelor <mshelor@cpan.org>.

SEE ALSO

       shasum is implemented using the Perl module Digest::SHA or Digest::SHA::PurePerl.