Man page for crc32(1)

NAME

sha1, sha256, crc32 - compute hashes or checksums of streams and files

SYNOPSIS

sha1 [options] [file...]
sha256 [options] [file...]
crc32 [options] [file...]

DESCRIPTION

sha1, sha256, and crc32 are utilities for computing the SHA-1 cryptographic hash function, the SHA-256 cryptographic hash function, and the CRC-32 checksum, respectively. They operate on character streams of any length. sha1 computes a 20-byte hash, sha256 computes a 32-byte hash, and crc32 computes a 4-byte checksum.

The output is a sequence of lines, one for each file, of the form

347b40d5e85365fa11e2c1cf6cb8c80c288c39fb filename

If no filename is given on the command line, the input is read from stdin.

OPTIONS

The following options are supported:

-h, --help

Help. Print usage information and exit.

-v, --version

Print version and copyright info and exit.

-l, --license

Print license and copyright info and exit.

-r, --recursive

Traverse subdirectories recursively.

-q, --quiet

Suppress warnings.

EXIT STATUS

The exit status is 1 if an illegal command line was given, and otherwise 0. Errors, such as missing files, are reported, but do not lead to a non-zero exit status.

STANDARDS

sha1 and sha256 aim to conform to the U.S. Government's Secure Hash Standard, FIPS PUB 180-2, although this has not been officially certified. Unlike the standard, these programs can (in principle) handle input streams that are longer than 2^64 bits. See http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf.

VERSION

0.3

AUTHOR

Peter Selinger,

COPYRIGHT AND LICENSE

Copyright (C) 2000-2007 Peter Selinger.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. See also http://www.gnu.org/.