grep, etc

[Bob Stockler]

On Wed, Aug 18, 2004 at 12:09:47PM -0400, Brian K. White wrote:
| Jay R. Ashworth wrote:
| > On Wed, Aug 18, 2004 at 01:17:23AM -0400, Brian K. White wrote:
| >> Jay R. Ashworth wrote:
| >>> On Tue, Aug 17, 2004 at 11:08:11PM -0400, Brian K. White wrote:
| >>>> Fairlight wrote:
| >>>>> Sweet.  I should grab that.  :)  Basically a -useful- egrep.  :)
| >>>>> Well, egrep is useful, but not as useful as it otherwise could be.
| >>>>
| >>>> I'd say the plain old stock sco grep was useful, since it aswered
| >>>> the need very directly in one command without especially exotic
| >>>> options or a pipeline. Didn't even require the stock egrep let
| >>>> alone gnu grep or pcregrep.
| >>>
| >>> Well, except that it *didn't* fulfill the requirement of the poster
| >>> who started this thread, without a big ungainly pipline wrapped
| >>> around it.
| >>
| >> What are you talking about?
| >>
| >> The stated request was:
| >>
| >> sample data:
| >> ISA*00000089** *
| >> CLM*inv123456*a*b*c         -213
| >> SV1*23456*25*A*B            -214
| >>
| >> I want to be able to view a range of lines, ie: from -213 to -216
| >>
| >> In what way does this fail to meet that request?
| >> grep '-21[3-6]$' file
| >
| > Well, in the *exact* instance he used as an example, it would work.
| >
| > But what happens if he wants -213 through -226?
| >
| > There isn't actually, quite enough information about his requirements
| > here to design a solution that's guaranteed to work.
| 
| head-smack
| you are right of course.
| Bob, "I lose!"
| 
| My next choice would have been awk by using * as the field delimiter, sub*()
| to pluck out the 216, and if() the variable is within the limits print $0. 3
| or 4 lines minimum, 5 I think if I can't find 216 by some better means than
| counting back from the end of the field.

I don't know what you're talking about here.  The beginning
and ending strings are the final fields on the lines, so $NF
would hold them.  

My initial solution was:

  1 - when beginning $NF is matched, print the line and set a flag
  2 - when ending $NF is matched, print the line and exit.
  3 - if flag is set print the line.

I have a little perl program (cgrep) that prints N (default 3)
lines on each side of a line matching a pattern.  If you want
an uneven number of lines that would be fine (though slower that
the AWK program), but if you wanted an even number of lines its
output would have to be piped through grep -v to remove either
the first or last line.

Bob

-- 
Bob Stockler - bob at trebor.iglou.com
Author: MENU EDIT II - The BEST Creator/Editor/Manager for filePro User Menus.
Fully functional (time-limited) demos available by email request (specify OS).