md5sum - generates or checks MD5 message digests
md5sum [-bv] [-c [file]] | [file...]
md5sum generates or checks MD5 checksums. The algorithm to generate the
checksum is reasonably fast and strong enough for most cases. Exact
specification of the algorithm is in RFC 1321.
Normally md5sum generates checksums of all files given to it as a
parameter and prints the checksums followed by the filenames. If, however,
-c is specified, only one filename parameter is allowed. This
file should contain checksums and filenames to which these checksums
refer to, and the files listed in that file are checked against the
checksums listed there. See option -c for more information.
OPTIONS [Toc] [Back]
-b Use binary mode. In unix environment, only difference between
this and the normal mode is an asterix preceding the filename in
-c Check md5sum of all files listed in file against the checksum
listed in the same file. The actual format of that file is the
same as output of md5sum. That is, each line in the file
describes a file. A line looks like:
<MD5 checksum> <filename>
So, for example, if a file was created and its message digest
calculated like so:
echo foo > md5-test-file; md5sum md5-test-file
md5sum would report:
-v Be more verbose. Print filenames when checking (with -c).
The related MD4 message digest algorithm was broken in October 1995.
MD5 isn't looking as secure as it used to.
This manpage is not quite accurate and has formatting inconsistent with
md5sum does not accept standard options like --help.
md5sum was originally written by Branko Lankester, and modified afterwards
by Colin Plumb and Ian Jackson (firstname.lastname@example.org). Manual
page was added by Juho Vuori (email@example.com)
Lankester et al 29th November 1995 MD5SUM(1)
[ Back ]