This is version 2.01 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.
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 ';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 18.104.22.168)
as agrep/agrep-2.01.tar.Z (or in uncompressed form as agrep/agrep-2.01.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 [email protected] or to [email protected]
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 found and fixed:
1. multiple definitions of some global variables.
(though haven't caused real problems)
2. -G option doesn't work.
(compat.c do too much checking. After remove the checking of
-c option against -G option, and it works.)
3. -w option forced the first character in the pattern to match.
remove the restriction.
January 23, 1992