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...";

foreach ( @i ) {
  my @proc = /^
            (\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;

    print join ' | ', map { defined() ? $_ : 'undef' } @proc;
    print "\n";
}

##</code><code>##

wwwrun | 17275 | 2006 | undef | undef | undef | undef | /usr/sb...
root | 3826 | undef | undef | undef | Jan08 | undef | su -
root | 3826 | undef | undef | undef | undef | Jan 08 | su -
root | 3547 | undef | 06:49 | undef | undef | undef | zmd /us...
root | 3547 | undef | undef | 06:49:12 | undef | undef | zmd /us...

##</code><code>##

foreach ( @i ) {
  my @proc = /^
            (\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;

    print join ' | ', @proc;
    print "\n";
}

##</code><code>##

wwwrun | 17275 | 2006 | /usr/sb...
root | 3826 | Jan08 | su -
root | 3826 | Jan 08 | su -
root | 3547 | 06:49 | zmd /us...
root | 3547 | 06:49:12 | zmd /us...