shasum - Man Page

• Calculate the SHA1 checksum for one or more files: shasum path/to/file1 path/to/file2 ...
• Calculate the SHA256 checksum for one or more files: shasum --algorithm 256 path/to/file1 path/to/file2 ...
• Calculate the SHA512 checksum for one or more files: shasum --algorithm 512 path/to/file1 path/to/file2 ...
• Calculate a SHA1 checksum from stdin: command | shasum
• Calculate and save the list of SHA256 checksums to a file: shasum --algorithm 256 path/to/file1 path/to/file2 ... > path/to/file.sha256
• Read a file of SHA1 sums and filenames and verify all files have matching checksums: shasum --check path/to/file
• Only show a message for missing files or when verification fails: shasum --check --quiet path/to/file
• Only show a message when verification fails, ignoring missing files: shasum --ignore-missing --check --quiet path/to/file

tldr.sh

 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
       --tag         create a BSD-style checksum
   -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

 The following five options are useful only when verifying checksums:
       --ignore-missing  don't fail or report status for missing files
   -q, --quiet           don't print OK for each successfully verified file
   -s, --status          don't output anything, status code shows success
       --strict          exit non-zero for improperly formatted checksum lines
   -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),
 and name for each FILE.  The line starts with a `\' character if the
 FILE name contains either newlines or backslashes, which are then
 replaced by the two-character sequences `\n' and `\\' respectively.

 Report shasum bugs to mshelor@cpan.org

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

Copyright (C) 2003-2023 Mark Shelor <mshelor@cpan.org>.

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