On Fri, 2008-08-01 at 02:53 -0700, John W. Krahn wrote:
> Anirban Adhikary wrote:
> > Dear list
>
> Hello,
>
> > while I am running the following code I am getting a warning message. the
> > code is as follows
> >
> > 1 use strict;
> > 2 use warnings;
> > 3 use Cwd 'abs_path';
> > 4 my $dir = "/home/oraoneload_beta/sraywork/beta2.2/OraOneLoadServer";
> > 5 chdir($dir);
> > 6 #my $filename="$dir/processinfo.txt";
> > 7 #`ps -U oraoneload_beta -u oraoneload_beta u | grep perl | grep -v grep
> >> $filename`;
> > 8 open(FH,"ps -U oraoneload_beta -u oraoneload_beta u | grep perl | grep
> > -v grep|") or "can't open : $!";
> > 9 #open(FH,"$filename");
> > 10 my @process = <FH>;
> > 11 close(FH);
> > 12 chomp(@process);
> > 13 pop(@process);
> > 14 foreach my $el(@process)
> > 15 {
> > 16 my $cmd =(split /\s+/,$el)[12];
> > 17 my ($a,$b) = split(/\//,$cmd);
> > 18 my $path=abs_path($b);
> > 20 print $path."\n";
> > 21 }
> > 22
> >
> > The warning message is as Useless use of string in void context at
> > processcheck.pl line 8. But while I am commenting the line 8 and
> > uncommenting the the line 6, 7 and 9 and then running this script I am not
> > getting any warning message. Where I am making the mistake?
>
> Your mistake is on line 8 at:
>
> or "can't open : $!"
>
> You have to put something like 'die' between 'or' and '"'.
>
>
> Also, you may do better with code like this instead:
>
> use strict;
> use warnings;
> use Cwd 'abs_path';
>
> my $dir = '/home/oraoneload_beta/sraywork/beta2.2/OraOneLoadServer';
> chdir $dir or die "Cannot chdir to '$dir' $!";
>
> open my $FH, '-|', qw/ps -U oraoneload_beta -u oraoneload_beta -o
> command/ or die "Cannot open pipe from 'ps' $!";
>
> while ( <$FH> ) {
> next unless /perl/;
next if /grep/;
> chomp;
> my $cmd =( split ' ', $_, 3 )[ 2 ];
> my $path = abs_path( ( split /\//, $cmd )[ 1 ] );
> print "$path\n";
> }
>
> close $FH or warn $! ? "Error closing 'ps' pipe: $!"
> : "Exit status $? from 'ps'";
>
> __END__
>
>
>
> John
> --
> Perl isn't a toolbox, but a small machine shop where you
> can special-order certain sorts of tools at low cost and
> in short order. -- Larry Wall
>
--
Just my 0.00000002 million dollars worth,
Shawn
"Where there's duct tape, there's hope."
"Perl is the duct tape of the Internet."
Hassan Schroeder, Sun's first webmaster
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