while ( @ARGV ) { $arg = shift( @ARGV ); if ( $arg =~ /^-[acx]$/ ) { $opt{$arg} = 1; } elsif ( $arg eq "-help" ) { $opt{$arg} = 1; } elsif ( $arg eq "-f" ) { $opt{$arg} = shift( @ARGV ); } else { print "Unknown argument: $arg\n"; } }