Sha1sum command

From NetworkCommands

A command available on most Linux platforms; used to generate and display or check the SHA1 message digest (or checksum) of one or more files.

Usage Syntax

sha1sum [options] [path/]filename

Common options include;

• -b - read files in binary mode
• -t - read files in text mode (this is the default)
• -c - check against a given list contained within the specified filename
  • --status - only display a status code on success
  • -w - display warnings about improperly formatted checksum file lines

filename is either the file that you wish to generate and display a checksum for, or a file containing a list of checksums and filenames that you wish to check.

Usage Examples

sha1sum test.txt - compute and display the SHA1 checksum for file test.txt

sha1sum --check -w checksums.txt - check the checksums of the files and associated checksums listed in file checksums.txt and warn if lines in checksums.txt are improperly formatted

Usage Notes

The --status and -w options are only relevant when -c is used.

Here's an example checksum list file:

fdba2b328619f60823dd3254c63309e39a3ce2a3  test.txt
41ef29701323b6103a5404a59f0d994e6d20d63a *test2

The * indicates a binary file

An SAH1 checksum is always 160bits (or 20Bytes.)

Linux Usage Notes

With most Linux or Unix commands;

• Brief help can be displayed using the option/keyword: -h or --help, for example: chmod --help
• A full command manual can be displayed using the man command followed by the command name, for example: man chmod
• Sometimes 'info' pages are used instead of or to provide more information than man pages; for example: info chmod
• Version information can be display using the option/keyword: -v or --version, for example: chmod --version

Typical Output

[user@test] ~ # sha1sum test.txt

fdba2b328619f60823dd3254c63309e39a3ce2a3  test.txt

[user@test] ~ # sha1sum test2.txt

41ef29701323b6103a5404a59f0d994e6d20d63a  test2.txt

[user@test] ~ # more checksums.txt

fdba2b328619f60823dd3254c63309e39a3ce2a3  test.txt
41ef29701323b6103a5404a59f0d994e6d20d63a  test2.txt

[user@test] ~ # sha1sum --check -w checksums.txt

test.txt: OK
test2.txt: OK

Related Files

sha1sum is normally located here: /usr/bin/sha1sum

Related Commands

The md5sum command performs the same function for MD5 message digests.

The OpenSSL dgst command performs the same function while also supporting many other digests.

Related Articles

Information on other Linux commands

Information on other Secure Platform commands

Information on F5 BigIP commands

Information on Cisco commands

Information on Vyatta commands

Information on Extreme commands

Information on Blue Coat SGOS commands

Information on Nokia IPSO commands

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