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Top Forums Shell Programming and Scripting Can I speed up my grep command? Post 302860939 by Don Cragun on Monday 7th of October 2013 03:18:33 PM
Old 10-07-2013
If you're looking for a fixed string (rather than a match against a regular expression), use grep -F or fgrep (depending on which operating system you're using).

If you're trying to match the 1st few characters in a file and you have relatively large files and you have a lot of files that won't match, then using read or head to get the start of a file might make sense, but firing up grep and head for every input file is going to be slower than letting grep read the entire file unless the file you're processing is large.
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GZGREP(1)						      General Commands Manual							 GZGREP(1)

NAME
gzgrep, gzegrep, gzfgrep - search possibly compressed files for a regular expression SYNOPSIS
gzgrep [ grep_options ] [ -e ] pattern filename... DESCRIPTION
gzgrep is used to invoke the grep on compress'ed or gzip'ed files. All options specified are passed directly to grep. If no file is speci- fied, then the standard input is decompressed if necessary and fed to grep. Otherwise the given files are uncompressed if necessary and fed to grep. If gzgrep is invoked as gzegrep or gzfgrep then egrep or fgrep is used instead of grep. If the GREP environment variable is set, gzgrep uses it as the grep program to be invoked. For example: for sh: GREP=fgrep gzgrep string files for csh: (setenv GREP fgrep; gzgrep string files) AUTHOR
Charles Levert (charles@comm.polymtl.ca) SEE ALSO
grep(1), egrep(1), fgrep(1), gzdiff(1), gzmore(1), gznew(1), gzforce(1), gzip(1), gzexe(1) ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +--------------------+-----------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +--------------------+-----------------+ |Availability | SUNWgzip | +--------------------+-----------------+ |Interface Stability | External | +--------------------+-----------------+ NOTES
Source for gzip is available in the SUNWgzipS package. GZGREP(1)
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