First, what are the errors you see? I know of at least two ones ...

Why don't you just write this in sed or awk or some other shell scripting language? I mean, that's basically what your Perl script is ...

If you wanted to write this in Perl, I'd do something like the following:

use strict;
use warnings;

my $app = 'nscd';
print "Looking for '$app'\n";
while (1)
{
    open PS, "ps -ef |"
        || die "Cannot open ps command: $!\n";
    my @cmd =
        grep { /$app/ }
            <PS>;
    close PS;

    last unless @cmd;

    print "'$app' is still running ...\n";
    sleep 2;
}

print "'$app' is finished.\n";
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The first problem is that you've written a shell script in Perl. Perl can do all those things: grep, awk, sleep without all the backticks. And if you are adventuresome, you can use a module to replace the functionality of ps too.

Now onto your actual bug. You need to use "eq" to do your string comparison. "==" does a numerical comparison and since neither string has any numbers in it you get "0 == 0" and therefore it's true.

while ($RUNDBCOLD eq (`ps -ef | grep -v grep | grep "nscd" | awk -F/ '
+{print \$4}'`))
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HTH

Glad you figured it out!

Here's another idea - just something to think about. On my system (Red Hat Linux 9) there's an 'nscd' start/stop/status script in /etc/rc.d/init.d. So at a command prompt I can do

   service nscd status
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and if the nscd daemon is running, the return code will be zero(0) - if it's not running, the return code will be some positive number. So, you could do something like this:

   #!/usr/bin/perl -w
   @args = ("/sbin/service", "nscd", "status");
   while (system(@args) == 0) {
      print "job still running!\n";
      sleep 2;
   }
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HTH.

As other posters have pointed out, Perl isn't shell, although it can be used that way.

You make calls, via backticks (``) to external commands - even to call text processing tools such as awk, when you could do most of it internally with perl.

There are modules on CPAN that allow you to look at the process list on UNIX systems (see Proc::ProcessTable)

dragonchild has give you a good example - you should work through the way his example works and learn from it.

Cheers

BazB

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