Science Fair Project Encyclopedia
Filter (Unix)
In UNIX and UNIX-like operating systems, a filter is program that gets most of its data from standard input and writes its main results to standard output. UNIX filters are often used as elements of pipelines.
The classic filter would be grep; here's an example:
cut -d : -f 1 </etc/passwd | grep foo
This finds all registered users that have "foo" as part of their username.
Common UNIX filter programs are: cat, cut, grep, head, sort, uniq and tail. Programs like awk and sed can be used to build quite complex filters because they are fully programmable.
A more complete list of UNIX filter programs:
See also: http://wiki.debian.net/index.cgi?filter
10-26-2009 08:16:03
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The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details