for ( $sysDescr ) {

[download]
This line doesn't make any sense to me.
Try adding a lot debug prints to your script and then look if every variable contains what you expect and if your script walks the ways you want. For example: 
foreach $hostName (@serverList) {
    print STDERR "--- Server: $hostName\n";

    # snmpwalk as filehandle
    #----------------------------------
    $FH_SNMPWALK = new FileHandle "$SNMPWALK $hostName $oidNbrSysDescr
+ 2>&1|";
    die "$0: $! in Zeile: ", __LINE__ unless defined $FH_SNMPWALK;

    # execute snmpwalk 
    #----------------------------------
    while( $sysDescr = <$FH_SNMPWALK> ) {
      chomp $sysDescr;
      print STDERR "   Desc: $sysDescr\n";

      for ( $sysDescr ) {
           print STDERR "   in_for: $_\n";

[download]
Giving the output some intend makes it easier to read when debugging nested loop/if situations. As long as you have no clue what is going wrong, up to one print in each loop or if block is a good thing. In many cases, the processing works, but the output isn't what you expect. Monitoring your $OutputLine variable may also be a good idea.

Besides of your probleme, you could shorten your code a little bit:

         if (s/$prefixSysDescr/$hostName$TAB/ or s/snmpwalk:\s*/$hostN
+ame$TAB/) {
            $OutputLine = $_;
            last;
         }; # substitute some prefixes (this one works)

[download]
...or even shorter... 
         if (s/($prefixSysDescr|snmpwalk:\s*)/$hostName$TAB/) {
            $OutputLine = $_;
            last;
         }; # substitute some prefixes

[download]

In reply to Re: His strangeness regex by Sewi
in thread His strangeness regex by o_chfa

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