Dear Monks
Below I try to parse the output from the ps command. Because Unix and Linux use different time-formats I need to built in some flexibility in my parsing expression. Here is the test-code I use: 
#! /usr/bin/perl -lw

use strict ;
use warnings ;

my @i ;
#        usern      pid     ?  ? startt   ?          ?     command
$i[0] = "wwwrun   17275 10449  0 2006     ?      00:00:00 /usr/sb...";
$i[1] = "root      3826     1  0 Jan08    ?      00:00:00 su -" ;
$i[2] = "root      3826     1  0 Jan 08   ?      00:00:00 su -" ;
$i[3] = "root      3547     1  2 06:49    ?      00:11:56 zmd /us...";
$i[4] = "root      3547     1  2 06:49:12 pts/1  00:11:56 zmd /us...";

my $usern ;
my $pid ;
my $time ;
my $command ;
foreach ( @i ) { 
  ($usern, $pid, $time, $command) = ( $_ =~ /^
            (\w+)            # capture username
            \s+
            (\d+)            # capture PID
            \s+\d+\s+\d+\s+
            (?:              # cluster (not capturing)
              (\d{4})              # capture %Y
              |                    # or
              (\d{2}:\d{2})        # capture %H:%M
              |                    # or
              (\d{2}:\d{2}:\d{2})  # capture %H:%M:%S
              |                    # or
              (\w{3}\d{2})         # capture %b%d
              |                    # or
              (\w{3}\s+\d{2})      # capture %b %d
            )
            \s+\S+\s+\S+\s+  # skip 2 columns after the 5th column
            (.*)             # capture the command
    $/gx ) ;
    printf "usern=%s pid=%s, time=%s command=%s\n",
        ($usern || ""), ($pid || ""), 
        ($time || ""), ($command || "")  ;
}

[download]
The output is:
usern=wwwrun pid=17275, time=2006 command=
usern=root pid=3826, time= command=
usern=root pid=3826, time= command=
usern=root pid=3547, time= command=06:49
usern=root pid=3547, time= command=

[download]
I think I do something fundamentally wrong when parsing the date/time column.....
Any suggestion ?

Thnx
LuCa

this question is the continuation of how many instances are running ?

In reply to parsing variable input (perlre problem) by jeanluca

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