How can I store the result of a system command in a Perl variable?

Question

$ cat test.pl
my $pid = 5892;
my $not = system(\"top -H -p $pid -n 1 | grep myprocess | wc -l\");
print \"not = $not\\n\";
$ perl test.pl
11
not = 0
$

Answer 1

Use backtick for system commands which helps to store their result into Perl variable.

my $pid = 5892; my $not = ``top -H -p $pid -n 1 | grep myprocess | wc -l`; print "not = $not\n";