Already mentioned: 
my $cmd = $step_no ? $step_no : 0;

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Simplifies to: 
my $cmd = $step_no || 0;

[download]
If $step_no is only false when $step_no is zero, then it can even be simplified to 
my $cmd = $step_no;

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In reply to Re: reduce line of code by ikegami
in thread reduce line of code by Sun751

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