in reply to Parsing output from a command

Ahh, the power of regular expressions: 

use strict;
use warnings;

my $data;
{
    local $/;
    $data = <DATA>;
}

my %drives = ();
while ($data =~ /^(\w+)\s*.*?Serial Number\.*(\w*)\s/smg) {
    $drives{$1} = $2;
}

while ( my ($key, $value) = each %drives) {
    print "$key  $value\n";
}

__DATA__
hdisk0   P1/Z1-Aa     16 Bit LVD SCSI Disk Drive (18200 MB)

        Manufacturer................IBM
        Machine Type and Model......ST318305LC
        FRU Number..................09P4437
        Serial Number...............0009E05B
        Part Number.................09P4436

hdisk1  P1/Z1-Ab     16 Bit LVD SCSI Disk Drive (18200 MB)

        Manufacturer................IBM
        Machine Type and Model......ST318305LC
        FRU Number..................09P4437
        Serial Number...............0004A0D2
        Part Number.................09P4436

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For information on these marvels of modern science, read perlretut. What I've done in the above is:
  1. ^(\w+) - Find a line that starts with alphanumeric characters
  2. \s*.*? - Advance past the smallest amount of arbitrary text until:
  3. Serial Number - I encounter the phrase 'Serial Number'
  4. \.* - Advance past an arbitrary number of '.' characters
  5. (\w*)\s - Find a series of alphanumerics followed by whitespace
The parenthesis capture the results into the variables $1 and $2, which are stored in the hash. The modifiers s and m control how new-lines are treated for matching, and the g modifier makes the while loop repeat so long as a match exists. Also note I localized the default record separator $/, so the entire data section is read in as a single string.

Replies are listed 'Best First'.
Re^2: Parsing output from a command
by Nkuvu (Priest) on Mar 24, 2009 at 16:18 UTC

    Another approach would be to join the lines of the result and match against that. For example:

    #!/usr/bin/perl
use strict;
use warnings;

# Slurp!
my @results = <DATA>;
my $results_string = join '', @results;

# Note: Direct assignment to hash works due
# to exactly two matches. Error checking would
# not be a bad idea, either (what happens if the
# match fails?)
my %matches = $results_string =~ /(hdisk\d+).+?Serial Number\.+(\w+)/g
+s;

for my $device (keys %matches) {
    print "$device  $matches{$device}\n";
}
__DATA__
hdisk0   P1/Z1-Aa     16 Bit LVD SCSI Disk Drive (18200 MB)

        Manufacturer................IBM
        Machine Type and Model......ST318305LC
        FRU Number..................09P4437
        Serial Number...............0009E05B
        Part Number.................09P4436

hdisk1  P1/Z1-Ab     16 Bit LVD SCSI Disk Drive (18200 MB)

        Manufacturer................IBM
        Machine Type and Model......ST318305LC
        FRU Number..................09P4437
        Serial Number...............0004A0D2
        Part Number.................09P4436

    [download]

    Output:

    hdisk1  0004A0D2
hdisk0  0009E05B

    [download]

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