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SGI Developer Toolbox 6.1 - Disc 4.iso
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agrep
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README
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agrep -- version 2.04
This is version 2.04 of agrep - a new tool for fast text searching
allowing errors. agrep is similar to egrep (or grep or fgrep), but
it is much more general (and usually faster).
The main changes from version 1.1 are
1) incorporating Boyer-Moore type filtering to speed up search
considerably,
2) allowing multi patterns via the -f option; this is similar
to fgrep, but from our experience agrep is much faster,
3) searching for "best match" without having to specify the
number of errors allowed, and
4) ascii is no longer required. Several more options were added.
To compile, simply run make in the agrep directory.
The three most significant features of agrep that are not supported
by the grep family are:
[1] the ability to search for approximate patterns;
for example,
"agrep -2 homogenos foo"
will find homogeneous as well as any other word that can be
obtained from homogenos with at most 2 substitutions,
insertions, or deletions.
"agrep -B homogenos foo"
will generate a message of the form:
best match has 2 errors, there are 5 matches, output them? (y/n)
[2] agrep is record-oriented rather than just line oriented;
a record is by default a line, but it can be user defined;
for example,
"agrep -d '^From ' 'pizza' mbox"
outputs all mail messages that contain the keyword "pizza".
Another example:
"agrep -d '$$' pattern foo"
will output all paragraphs (separated by an empty line) that
contain pattern.
[3] multiple patterns with AND (or OR) logic queries;
for example,
"agrep -d '^From ' 'burger,pizza' mbox"
outputs all mail messages containing at least one of the two
keywords (, stands for OR).
"agrep -d '^From ' 'good;pizza' mbox"
outputs all mail messages containing both keywords.
Putting these options together one can ask queries like
agrep -d '$$' -2 '<CACM>;TheAuthor;Curriculum;<198[5-9]>' bib
which outputs all paragraphs referencing articles in CACM between
1985 and 1989 by TheAuthor dealing with curriculum. Two errors are
allowed, but they cannot be in either CACM or the year (the <>
brackets forbid errors in the pattern between them).
Other features include searching for regular expressions (with or
without errors), unlimited wild cards, limiting the errors to only
insertions or only substitutions or any combination, allowing each
deletion, for example, to be counted as, say, 2 substitutions or 3
insertions, restricting parts of the query to be exact and parts to
be approximate, and many more.
agrep is available by anonymous ftp from cs.arizona.edu
(IP 192.12.69.5) as agrep/agrep-2.04.tar.Z (or in uncompressed form
as agrep/agrep-2.04.tar). The tar file contains the source code
(in C), man pages (agrep.1), and two additional files,
agrep.algorithms and agrep.chronicle, giving more information. The
agrep directory also includes two postscript files: agrep.ps.1 is
a technical report from June 1991 describing the design and
implementation of agrep; agrep.ps.2 is a copy of the paper as
appeared in the 1992 Winter USENIX conference.
Please mail bug reports (or any other comments) to sw@cs.arizona.edu
or to udi@cs.arizona.edu.
We would appreciate if users notify us (at the address above) of any
extensions, improvements, or interesting uses of this software.
January 17, 1992
BUGS_fixed/option_update
1. remove multiple definitions of some global variables.
2. fix a bug in -G option.
3. fix a bug in -w option.
January 23, 1992
4. fix a bug in pipeline input.
5. make the definition of word-delimiter consistant.
March 16, 1992
6. add option '-y' which, if specified with -B option, will always
output the best-matches without a prompt.
April 10, 1992
7. fix a bug regarding exit status.
April 15, 1992