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=                               Agrep                                =
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                            Introduction
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agrep (approximate grep) is an open-source approximate string matching
program, developed by Udi Manber and Sun Wu between 1988 and 1991, for
use with the Unix operating system. It was later ported to OS/2, DOS,
and Windows.

It selects the best-suited algorithm for the current query from a
variety of the known fastest (built-in) string searching algorithms,
including Manber and Wu's bitap algorithm based on Levenshtein
distances.

agrep is also the search engine in the indexer program GLIMPSE. agrep
is under a free ISC License.


                    Alternative implementations
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A more recent agrep is the command-line tool provided with the TRE
regular expression library. TRE agrep is more powerful than Wu-Manber
agrep since it allows weights and total costs to be assigned
separately to individual groups in the pattern. It can also handle
Unicode. Unlike Wu-Manber agrep, TRE agrep is licensed under a
2-clause BSD-like license.

FREJ (Fuzzy Regular Expressions for Java) open-source library provides
command-line interface which could be used in the way similar to
agrep. Unlike agrep or TRE it could be used for constructing complex
substitutions for matched text. However its syntax and matching
abilities differs significantly from ones of ordinary regular
expressions.


                              See also
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* Bitap algorithm
* TRE (computing)


                           External links
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* Wu-Manber agrep
**[http://www.tgries.de/agrep AGREP home page]
**[https://web.archive.org/web/20170706092701/ftp://ftp.cs.arizona.edu/agrep
For Unix]  (To compile under OSX 10.8, add -Wno-return-type to the
CFLAGs  = -O line in the Makefile)
*See also
**[http://laurikari.net/tre TRE regexp matching package]
**[https://web.archive.org/web/20080513225010/http://www1.bell-labs.com/project/wwexptools/cgrep/
cgrep a defunct command line approximate string matching tool]
**[http://www.dcc.uchile.cl/~gnavarro/software/ nrgrep] a command line
approximate string matching tool
**[http://finzi.psych.upenn.edu/R/library/base/html/agrep.html agrep
as implemented in R]


License
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Original Article: http://en.wikipedia.org/wiki/Agrep