yeah, thank you.that's the way I want.now I realized the necessity of using reffed subroutine. 
my %run = (x => \&system, X => \&myrun);
my ($run, @args);
foreach(@ARGV){
if (/^-([xX])$/){
   $run = $run{$1}
}elsif (/^-/){
   push @args, $_
}
$run->(@args)

[download]
It's using prepared hash to switch run command, that's the logical way instead of using 'if ($run eq 'x'){system ...}', the ugly way I tried to avoid.

In reply to Re^2: how to assign 'system' to a value, and eval it. by vincentaxhe
in thread SOLVED:how to assign 'system' to a value, and eval it. by vincentaxhe

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