Editing Grep (section)

===agrep===
{{main|agrep}}
'''agrep''' (approximate grep) is an [[open-source software|open-source]] [[approximate string matching]] program, developed by [[Udi Manber]] and Sun Wu between 1988 and 1991,<ref>{{cite conference |title=Agrep -- a fast approximate pattern-matching tool |last1=Wu |first1=Sun |last2=Manber |first2=Udi |date=20–24 January 1992 |location=San Francisco, California |conference=1992 Winter USENIX Conference |citeseerx = 10.1.1.89.5424}}</ref> for use with the [[Unix]] operating system. It was later ported to [[OS/2]], [[DOS]], and [[Microsoft Windows|Windows]].

''a''grep matches even when the text only ''approximately'' fits the search pattern.<ref name=eGrep.SunX>{{cite magazine |magazine=Sun Expert|author=S. Lee Henry |date=June 1998 |pages=35–26|title=Proper Searching}}</ref>

This following invocation finds <code>netmasks</code> in file <code>myfile</code>, but also any other word that can be derived from it, given no more than two substitutions.
<pre>agrep -2 netmasks myfile</pre>
This example generates a list of matches with the closest, that is those with the fewest, substitutions listed first. The command flag <code>-B</code> means "best":
<pre>agrep -B netmasks myfile</pre>