elittle has asked for the wisdom of the Perl Monks concerning the following question:

Thanks in advance for any and all help. I am troubleshooting someone elses perl program and they didn't give a lot of comments in their code, whether to comment or not is a hotly debtaed topic so I will not put my views into this post. I have only been using perl for the last year and a half and only when there is a problem with the incumbent scripts.

Here is the error: Use of uninitialized value in concatenation (.) or string at report.pl line 185.

Here is the code at that line: $bkp_info = `sed -e :a -e "$d;N;2,3ba" -e "P;D" /db2/$DB2DBDFT/Messages/temp.txt`;

The script does perform as expected, I only found out about this error while troubleshooting why the script wasn't calculating the MB used by the largest table. I have since fixed that problem but found this issue after fixing the first.

Originally there were only singles ticks around the regular expression and I changed them to double quotes because I thought perl was interpreting the $d as a variable but that was not the case.

I cannot find the uninitialized value nor where a string is being concatenated so I don't know what to do next or where to go with this issue.

I will answer any questions to the best of my ability. Here is the full program: 

#!perl -w
######################################################################
+############
#  Script Name:  report.pl                                            
+           #
#  Converted by: Sharath Jayatheertha                                 
+           #
#  Date modified: 12-Jan-2006                                         
+           #
#  Description:  Generates report on WBI databases.                   
+           #
#  Last updated by: Erik Little                                       
+           #
#  Date Updated:  March 22 , 2010                                     
+           #
#  Notes:  Modified Largest Table section to calculate the MB of the l
+argest     #
#  table.                                                             
+           #
#                                                                     
+           #
#                                                                     
+           #
######################################################################
+############
# Bring in Global Variables.
######################################################################
+############
unshift (@INC, "/db2/$DB2DBDFT/Scripts");
require 'variables.pl';
use Env;

$file = "/db2/$DB2DBDFT/Messages/report.txt";
$temp = "/db2/$DB2DBDFT/Messages/temp.txt";

$time = scalar(localtime);
$request = 0;
$size = 0;

open FILE, ">$file";
print FILE "\t\t\t\tReport\n\n\n";

######################################################################
+###
#                Filesystem Exceeding 90% Utilization.                
+  #
######################################################################
+###
foreach (@FILESYSTEMS)
{
        ######################################
        # Obtain % Used for each filesystem. #
        ######################################
        $rc = `df -k | grep $_`;

        if ($rc =~ / (\d*)\%/)
        {
                if ($1 > 90)
                {
                        $mounts{$_}=$1;
                        $request = 1;
                }
        }
}
if ($request == 1)
{
        print FILE "File Systems Exceed 90 Pct Utilization.\n";
        print FILE "A Disk Request May Need To Be Created\n";
        foreach (keys %mounts)
        {
                print FILE "$_  $mounts{$_}\n";
        }
}
foreach $db (@dblst)
{
        $rc = `db2 connect to $db`;
        if($rc =~ /Database Connection Information/)
        {
                print FILE "\n----------------------------------------
+----------------------------------------------------------";
                print FILE "\n\t\t\t\t$db Database\n";
                print FILE "------------------------------------------
+--------------------------------------------------------\n";
                ######################################################
+###################
                # Largest Table                                       
+                  #
                ######################################################
+###################

                undef $rc;
                undef $rc1;
                undef $size;
                undef $mb;
                $rc1 = `db2 "select name as a from sysibm.systables wh
+ere npages = (select max(npages) from sysibm.systables)"`;
                if ($rc1 =~ /(\/\w\S+|\w\S+)/)
                {
                        printf FILE "Biggest Table:\nName: $1\n";
                        $rc = `db2 "select npages from sysibm.systable
+s where npages = (select max(npages) from sysibm.systables)"`;
                        if ($rc =~ /(\d\d*)/)
                        {
                                $size = $1;
                                $mb = (($size * 4096)/1024/1024);
                                $result = sprintf("%.2f", $mb);
                                printf FILE "Size: $result MB\n";
                        }
                }

                ######################################################
+###################
                #                 Gather Tablespace Utilization Info. 
+                  #
                ######################################################
+###################
                $largespace = 0;
                $highutil = 0;
                $dbsize = 0;
                undef $name;
                undef $type;
                undef $totalpages;
                undef $useablepages;
                undef $usedpages;
                undef $percentused;
                undef $highspaces;
                undef $size;
                undef $largespaces;
                undef $pagesize;
                open IN, "db2 list tablespaces show detail |";
                while (<IN>)
                {
                        if (/Name *= (\S*)/)
                        {
                                $name= $1;
                        }
                        if (/Type *= (\w*)/)
                        {
                                $type= $1;
                        }
                        if (/Total pages *= (\w*)/)
                        {
                                $totalpages = $1;
                        }
                        if (/Useable pages *= (\w*)/)
                        {
                                $useablepages = $1;
                        }
                        if (/Used pages *= (\w*)/)
                        {
                                $usedpages = $1;
                                $percentused = int(100 * ($usedpages/$
+useablepages));
                                if (($percentused > 75) && ($type ne "
+System"))
                                {
                                        $highutil = 1;
                                        $highspaces{$name}= $percentus
+ed;
                                }
                        }
                        if (/Page size \(bytes\) *= (\w*)/)
                        {
                                $pagesize = $1;
                                $size = int(($pagesize * $totalpages)/
+1024/1024);
                                if($size > 200)
                                {
                                        $largespace = 1;
                                        $largespaces{$name}= $size;
                                }
                                $dbsize = $size + $dbsize;
                        }
                }
                close IN;

                print FILE "\nCURRENT DATABASE SIZE:\n";
                print FILE "Total Size : $dbsize MB\n";

                ######################################################
+###################
                #                 Print Tablespaces Over 200MB.       
+                  #
                ######################################################
+###################
                if($largespace == 1)
                {
                        print FILE "\nTablespaces Exceeding 200MB:\n";
                        foreach (keys %largespaces)
                        {
                                print FILE "$_  $largespaces{$_} MB\n"
+;
                        }
                        %largespaces = ();
                }

                ######################################################
+###################
                #                 Print Overutilized Tablespaces.     
+                  #
                ######################################################
+###################
                if($highutil == 1)
                {
                        print FILE "\nTablespaces Exceeding 75 Pct Uti
+lization:\n";
                        foreach (keys %highspaces)
                        {
                                print FILE "$_  $highspaces{$_} PCT\n"
+;
                        }
                        %highspaces = ();
                }

                ######################################################
+###############
                #                           Back up Information       
+              #
                ######################################################
+###############
                $bkp = `db2 "list history backup all for $db " |tail -
+6`;
                open TEMP, ">$temp";
                print TEMP $bkp;
                close TEMP;

                print FILE "\nBackup Information:\n";
                $bkp_info = `sed -e :a -e "$d;N;2,3ba" -e "P;D" /db2/$
+DB2DBDFT/Messages/temp.txt`;
                if($bkp_info =~ /Start/)
                {
                        print FILE $bkp_info;
                }
                else
                {
                        print FILE "Backup Failed";
                }
                #unlink ($temp);

                print FILE "__________________________________________
+________________________________________________________\n";
                $rct = `db2 terminate`;
                if($rct !~ /TERMINATE command completed successfully/i
+)
                {
                        print FILE "Database Disconnection Error.\n";
                }
        }
        else
        {
                print FILE "Database Connection Error.\n";
        }
}

##########################################################
# Last Runtimes of Reorg's and Runstats                  #
##########################################################

print FILE "\nRuntime Information:\n";
if(-e $RUNFILE)
{
        open IN, $RUNFILE;
        while($lines=<IN>)
        {
                print FILE "Last Runstats and Reorgs under the $DB2DBD
+FT Instance: $lines\n";
        }
        close IN;
}
else
{
        print FILE "No Information Available For $DB2DBDFT Instance, P
+lease check the Error log File.\n";
}
unlink($RUNFILE);

print FILE "\n\nReport was generated on $time\n\n";

close FILE;

&alert();

#=====================================================================
+===
#  Module: send_email
#  Description: DRM is sent an e-mail informing them of changes.
#=====================================================================
+===
sub alert()
{
        open IN, $file;
        read IN, $msg, 10000;
        close IN;
        `printf "$msg" | mail -s "$DB2DBDFT - Report" $EMAILNOTIFY`;
}

[download]

Thanks, elittle

Replies are listed 'Best First'.
Re: Troubleshooting question
by ikegami (Patriarch) on Mar 23, 2010 at 15:26 UTC

    Originally there were only singles ticks around the regular expression and I changed them to double quotes because I thought perl was interpreting the $d as a variable but that was not the case.

    It's neither in single nor double quotes. It's in backticks. The contents of backticks are subject to interpolation. (After which they are executed as a shell command and their output is returned. See perlop) If you're trying to pass a literal dollar sign, escape it with a backslash.

[reply]
Re: Troubleshooting question
by JavaFan (Canon) on Mar 23, 2010 at 15:26 UTC
    Perl interpolates $d as a variable because it's inside backquotes. The inner quotes (the doubles in your case) are handled by the shell.

    In your case, it seems that either $d or $DB2DBDFT is undefined. Neither seems to be set by your program. I assume $DB2DBDFT is imported from the environment, which leaves $d. Typo? Should that be $db? Or something else?

[reply]
[d/l]
[select]
      $DB2DBFT is an evironment variable that is in the env file. $d is a swtich that is used with sed. I saw on another site where they had the switches inside '{switches}', so I tried that format but it still generated the error. Thanks for replying.
[reply]
        If you don't want any interpolation at all, use a temporary variable: 
        # single quotes prevent interpolation
my $sed_command = 'sed -e :a -e "$d;N;2,3ba" -e "P;D" /db2/$DB2DBDFT/M
+essages/temp.txt';
my $result = `$sed_command`; # passes a literal $d to sed, not the con
+tents of the $d perl variable.

        [download]
        Perl 6 - links to (nearly) everything that is Perl 6.
[reply]
[d/l]

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