Regular expression query

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

I am trying to do the following grep for my output


A> show chassis power | match "PEM|Online"

PEM 0:

PEM 1:

PEM 2:
  State:     Online

PEM 3:
  State:     Online
[download]

In the above output am trying to find which PEM is online. For this , i thought i split using /n and find the state Online and go back to previous matching and check which PEM is online . I did not complete the code as am stuck how to go back


    $rh->cmd('show chassis power | match "PEM|Online"');
    my $output = $rh->get_response;
    my @outputlist = split /\n+/, $output;
        foreach (0..$#outputlist) {
             if ($outputlist[$_] =~/ State:\s\w{4}Online/) {
                if($outputlist[$_ _1] =~ /PEM 1/
}
}
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Comment on Regular expression query Select or Download Code

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Re: Regular expression query by hippo (Archbishop) on Nov 12, 2017 at 18:11 UTC
If you split on the blank lines instead of on newlines then you don't have to go back: `#!/usr/bin/env perl use strict; use warnings; my $input = qq# PEM 0: PEM 1: PEM 2: State: Online PEM 3: State: Online #; for my $rec (split /\n\n/, $input) { next unless $rec =~ /State:\s+Online/; $rec =~ /(PEM \d+)/ or die "Bad input: no PEM in '$rec'!"; print "$1 is online\n"; }` [download]	[reply] [d/l]
Re: Regular expression query by BillKSmith (Monsignor) on Nov 12, 2017 at 22:35 UTC
With the /m flag, a regex can match over more than one line. `C:\Users\Bill\forums\monks>type 1203224.pl use strict; use warnings; my $output = <<'END_OUT'; PEM 0: PEM 1: PEM 2: State: Online PEM 3: State: Online END_OUT while ($output =~ m/^(PEM\s\d) \: $ \n ^ \s\sState: [ ]+ (Online)$/xmg +) { print "$1 $2\n"; } C:\Users\Bill\forums\monks>perl 1203224.pl PEM 2 Online PEM 3 Online` [download] Bill	[reply] [d/l]
Re: Regular expression query by KurtZ (Friar) on Nov 12, 2017 at 17:57 UTC
The simplest solution is to always parse the PEM and store it in a variable. Like this you only need to print that variable out if you have a match.	[reply]