From: Joseph Pecoraro <joepeck02@...>
Date: 2008-01-26T14:59:11+09:00
Subject: Re: regular expression negate a word (not character)

I just wrote up a quick script to do what I was thinking.  I decided to 
make a different utility only because of the complications that would 
arise with tons of switches on the command line if I were to add it to a 
find/replace utility.  (The user would have to say which regex they 
wanted for the actual replacement, and other inherent problems... moving 
on)

So without further ado, here is my example
------------------------------
joe[~/code/script]$ cat > input
winter tire
tire
retire
tired
snow tire
snow   tire
some snowtires

joe[~/code/script]$ grepall -2 tire --neg snow input
input [1]: winter tire
input [2]: tire
input [3]: retire
input [4]: tired

joe[~/code/script]$ grepall
usage: grepall [-#] ( [-n] regex ) [filenames]
  #         - the number of regular expressions, defaults to 1
  regex     - regular expessions to be checked on the line
  filenames - names of the input files to be parsed, if blank uses STDIN

options:
  --neg or -n     do not match this regular expression

special note:
  When using bash, if you want backslashes in the replace portion make 
sure
  to use the multiple argument usage with single quotes for the 
replacement.
------------------------------------------------------

The utility is hopefully easily to understand, although the usage is 
tough to present:
  - line by line processing
  - in the above example the -2 says there will be two regular 
expressions
  - the first is /tire/ and that needs to match
  - the second is /snow/ and that is Negated because of the --neg (or 
just -n) option
  - the last argument is the filename

The output needs to be tweaked, maybe so its  more like grep.  Right now 
it allows for multiple files so it prints the filename, [line number], 
and the line where there was a full match for all the regular 
expressions as correctly matched (negated where necessary).  Obviously 
this is very simple at the moment and it doesn't cover the specific 
situation you mentioned where there was the word tire and snowtire on 
the same line.

However if that is an issue you can:
  - find and replace all words SNOW with SPECIAL_STRING in all files
  - do what you have to do...
  - turn all SPECIAL_STRINGs back into SNOW in all files

That can be done rather easily.  You will have lost the case sensitivity 
in the word SNOW, but you can get around that by making your 
SPECIAL_STRING something like XsXnXoXwX based on the original case 
values of snow.  I hope that made sense.

Well I better get to bed, you made my night interesting!
-- 
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