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Can grep do numerical comparisons?

 
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Top Forums UNIX for Dummies Questions & Answers Can grep do numerical comparisons?
# 8  
Old 06-12-2008
grep uses regular expressions - which do not perform numerical operations by comparing the integer value of numbers and returning true/false, for example.

Regular-Expressions.info - Regex Tutorial, Examples and Reference - Regexp Patterns

What ripat did was clever textual analysis. None of this really matters because in unix there are almost always several ways to do something. Except that you are in a "debate". radulov is correct. regexes do not do numeric evaluation.

This is one acceptable definition of a regular expression from wikipedia:
Quote:
In computing, regular expressions provide a concise and flexible means for identifying strings of text of interest, such as particular characters, words, or patterns of characters
Note that a string is a set of characters "strung" together as in "a string of beads." That is the origin of the word string in CS. Nowhere is numeric evaluation performed.
 
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LEARN ABOUT V7

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  invokes  grep  on  compressed  or  gzipped  files.   These  grep	options  will  cause  zgrep  to  terminate  with  an  error  code:
       (-[drRzZ]|--di*|--exc*|--inc*|--rec*|--nu*).  All other options specified are passed directly to grep.  If no file is specified,  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 the GREP environment variable is set, zgrep uses it as the grep program to be invoked.

EXIT CODE

       2 - An option that is not supported was specified.

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), gzexe(1), gzip(1), zdiff(1), zforce(1), zmore(1), znew(1)

																	  ZGREP(1)