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/;
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
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