Several solutions

If you care about the program's output, use backticks, like so:

my $result = `ls /home`;
print $result;
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Otherwise, you can use system:

system('cp /tmp/foo /tmp/bar') || die "Can't run command";
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(although you should NEVER use cp when you can roll your own in perl)

Also, go see the thread on Running External Commands that has another method (pipe opens), plus valuable info on taint checking.