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- - Use of uninitialized value in pattern match - perl (https://www.linuxquestions.org/questions/programming-9/use-of-uninitialized-value-in-pattern-match-perl-888455/)

Use of uninitialized value in pattern match - perl

I want to strip the process name from the hosts - i did it with the code below.

I have two questions - is there a more compact way to strip off the process names? usalso i want to get rid of the errors after extracting the hostname. It is complaing about $arry[1]. using my $arry[1] is not allowed. Assigning the slice to a value, as is 'my $sliced_arry = $arry[1]; print $sliced_arry , does not work either.

Code:

 



#!/usr/bin/perl -w

use strict;

  open NEWCOMM, "newcomm_stat -n local mis100 |";

  while (<NEWCOMM>) {

            my @arry  = split (/\s+/ , $_);

            print "$arry[1]\n";

            }

(zeusUS@mit201

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 10

(odin@ibmis100

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 12

(thorUS@mit201

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 14

(balder@mis102

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 16

here i get what i want - just the host name, but still get those nasty errors. assigning a value to $1 does not work, and localizing $1 with 'my' is not allowed.

Code:

#!/usr/bin/perl -w

use strict;

  open NEWCOMM, "newcomm_stat -n localtick ibmis100 |";

  while (<NEWCOMM>) {

            my @arry  = split (/\s+/ , $_);

            if ($arry[1] =~ /\(\w+@(\w+)/){

                  my $newcomm_hosts =  $1;

                  print "$newcomm_hosts\n";

                  sleep 1;

            }

  }







mit102

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 10.

ibmis100

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 12.

ibmis100

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 14.

mit201

Use of uninitialized value in pattern match (m//) at newcomm_stats.pl3 line 7, <NEWCOMM> line 26.

For starters, you didn't give us info what line #7 is.

I suggest to

cat -n your_file.pl

and copy-paste screen output of the above here.
...
Read carefully 'perdoc -f split' - near the end. Check values of '@arry'. Consider using "split(' ', $whatever)" instead of "split(/\s+/, $whatever)" - you practically never need the latter (I don't remember such a case in my life).

thank you i am reading it now

Quote:

Originally Posted by casperdaghost (Post 4396321)

thank you i am reading it now

I meant

Code:

split(' ', $whatever);

, i.e. space as first argument.

I read the perl doc's for split, and ended up traversing the array with a for each loop - use strict seems to like that.
no more errors.

Code:

#!/usr/bin/perl -w

use strict;

 #open NEWCOMM , "/home/tops11/wjohnson/newcomm.ibfarm100:localtick";

 open NEWCOMM, "newcomm_stat -n localtick ibmis100 |";

  while (<NEWCOMM>) {

          ###my @arry  = split (/\s+/ , $_);

            my @arry  = split (' ' , $_);

            foreach my $line(@arry){

                my $sliced_newcomm = $arry[1];

                if ($sliced_newcomm =~ /\(\w+@(\w+)/){

                    my $newcomm_hosts =  $1;

                    print "$newcomm_hosts\n";

                    sleep 1;

                }

          }

  }