Parsing cisco router command output

routedude has asked for the wisdom of the Perl Monks concerning the following question:

Hello everyone,
I'm attempting to parse the output of 'show access-list' over a period of days to determine if a line in the access-list does not receive a hit over a period of time. Please see my earlier post: Parsing cisco log file

Below is the code I've come up with, I'm running into trouble with the last portion where I compare lines that have not received matches during day one to lines that haven't received matches on day two. I get nothing at all for output, any thoughts on where I have screwed up or how I can do this better would be much appreciated.

We're storing the output of sh access-list from a cisco #router in a file once a day for 30 days. This script will eventually look at all 30 files and output the access-list entries that have not recieved a match in all 30 files and therefore can be removed.

#/usr/bin/perl
#Prompt for the files we want to compare, for now just two

print "Enter filename that contains output of show access <list\n";
chomp ($aoutput = <STDIN>);
print "Enter the second file\n";
chomp ($aoutput1 = <STDIN>);

#Open our files
open (IN, $aoutput) || die "Couldn't open $aoutput $!";
open (LOG, ">>matches.txt") || die "Couldn't open matches.txt $!";
open (IN1, $aoutput1) || die "Couldn't open $aoutput1 $!";

#Push each line in file 1 that does not get any matches into an array

while (<IN>){
   push @aoutput unless /matches\)$/;
   }

#Push each line in file 2 that does not get any matches into an array

while (<IN1>){
   push @aoutput1 unless /matches\)$/;
       }

#See if the lines that didn't get matches on day 1
#didn't get matches on day 2 as well
#Gotta be a better way to do this?

while (<@aoutput>){
   $linetemp = grep {/$_/i} @aoutput1;
      if ($_ = $linetemp)
      {
      print $_;
      } 
  }
[download]

edited: Fri Mar 14 23:17:01 2003 by jeffa - code tags

Comment on Parsing cisco router command output Download Code

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Re: Parsing cisco router command output (potential answer, untested) by ybiC (Prior) on Mar 14, 2003 at 20:03 UTC
Hiya routedude, I added `<code>` tags around your example code, and tweaked some to make it clearer to my short-bus brain. I found this syntax for matching-the-intersection-of-two-arrays on page 106 of The Perl Cookbook, and also moved the file opens/closes as close to each ofther as possible - always a good habit. Anyways, I think this will do what you want or at least be close. Wiser monks than I might show how to make it scale to more than just two days' acl log files. The 'while... push unless /matches/' chunks could likely become a subroutine, but as is, this maybe shows some direction. cheers, ybiC striving toward Perl Adept (it's pronounced "why-bick") ==untested== #/usr/bin/perl -w use strict; # define output+input filenames: my $outFile = 'aclLog.txt'; print "Enter filename that contains output of show access <list\n"; chomp my $aclMatchesDay2 = <STDIN>; print "Enter the second file\n"; chomp my $aclMatchesDay2 = <STDIN>; # check for no-matches in first input file: open (ACLM1, $aclMatchesDay1) or die "Couldn't open $aclMatchesDay1: $ +!"; while (<ACLM1>){ push @noMatchesDay1 unless /matches/; } close ACLM1 or die "Couldn't close $aclMatchesDay1: $!"; # check for no-matches in second input file: open (ACLM2, $aclMatchesDay2) or die "Couldn't open $aclMatchesDay2: $ +!"; while (<ACLM2>){ push @noMatchesDay2 unless /matches/; } close ACLM2 or die "Couldn't close $aclMatchesDay2: $!"; # check for overlap betwixt two input files: my %isect; foreach $e (@noMatchesDay1, @noMatchesDay2){ $isect{$e}++; } my $noMatchesEver = keys %isect; # print said overlap to output file: open (OUT, ">>$outFile") or die "Couldn't open $outFile: $!"; print "$_\n" for @noMatchesEver; close OUT or die "Couldn't close $$outFile: $!"; [download]	[reply] [d/l]
Re: Parsing cisco router command output by Enlil (Parson) on Mar 14, 2003 at 20:31 UTC
Lets go through this line by line (much of this was caught with the warnings and strict pragmas) 1 #/usr/bin/perl 2 3 print "Enter filename that contains output of show access <list\n" +; 4 chomp ($aoutput = <STDIN>); 5 print "Enter the second file\n"; 6 chomp ($aoutput1 = <STDIN>); 7 8 open (IN, $aoutput) \|\| die "Couldn't open $aoutput $!"; 9 open (LOG, ">>matches.txt") \|\| die "Couldn't open matches.txt $!"; 10 open (IN1, $aoutput1) \|\| die "Couldn't open $aoutput1 $!"; 11 #Push each line in file 1 that does not get any matches into an ar +ray 12 while (<IN>){ 13 push @aoutput unless /matches\)$/; 14 } 15 #Push each line in file 2 that does not get any matches into an ar +ray 16 while (<IN1>){ 17 push @aoutput1 unless /matches\)$/; 18 } 19 20 #See if the lines that didn't get matches on day 1 didn't get matc +hes on day 2 as well 21 22 #Gotta be a better way to do this? 23 24 25 while (<@aoutput>){ 26 $linetemp = grep {/$_/i} @aoutput1; 27 if ($_ = $linetemp) { 28 print $_; 29 } 30 } [download] Line 1. You probably need to change this to `#!/usr/bin/perl` Though you might not depending on the system you are running (I know the AS Perl for windows will associate .pl files with perl). Line 2. You should add `use strict;` here :) Line 13. Warnings would have told you that this line does nothing: Useless use of push with no values at E:\111.pl line 13. What you probably meant was something like: `push @aoutput, $_ unless /matches\)$/;` [download] Line 17. See line 13, same issue. Line 25. I would assume you want a `for` loop as opposed to a `while` loop. Line 26. I would think that if there were anything in `@aoutput1` that everything would match. Also you wanted `@linetemp`, as opposed to `$linetemp`. Line 27. `$_=$linetemp` will always evaluate to true, as long as `$linetemp` something Perl considers true. Regardless this code will not do what you want. The way I would go about it is. == A Different Approach == 1. Open the day two file and grab all the lines you want and put them in a hash. Something like: `unless (/matches\)$/) { $no_match_day_two{$_} = 1 }` [download] 2. Open the day one files and do the same. 3. If i want to see the lines in day two that were not in day one, something like this would work (though with a few changes it can be made to show the ones in day one that were not in day two: `foreach my $match ( keys %no_match_day_two ) { print $match unless exists $no_match_day_one{$_}; }` [download] As for an array of day one stuff not in day two something like this would work: `@nmday_one_but_not_nmdtwo = grep { exists $no_match_day_two{$_} } keys + %no_match_day_one;` [download] I hope this helps. -enlil	[reply] [d/l] [select]
Re: Parsing cisco router command output by Vorlin (Beadle) on Mar 14, 2003 at 22:05 UTC
For your code at the bottom that runs the '`while (<@aoutput>)`', you could do somthething like this (my own test code): `@a = qw(a b c d e f); @b = qw(1 2 c 3 4 f); foreach $foo (@a) { if ( grep /$foo/, @b ) { print "Matched $foo in both arrays\n"; } }` [download] The above only works if both arrays are populated of course (but will return nothing if an either array is empty). There's probably better ways to do this but it's a good Q&D, hehe...	[reply] [d/l]