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SHASUM

Section: Perl Programmers Reference Guide (1)
Updated: 2017-08-16
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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)
   -U, --UNIVERSAL   read in Universal Newlines 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
   -p, --portable    read in portable mode (to be deprecated)

 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 PUB 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, `U' for UNIVERSAL, `^' for BITS, `?'
 for portable), 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