Re: Perl Input Parameters for Unix

[aitap]

Other than processing options using Getopt::Long (which I use most frequently) and Getopt::Std, options can be parsed manually. For example, in your case:

my ($input,$stat,$csv);
while (my $arg = shift @ARGV) {
if ($arg eq "-i") {
 $input = shift @ARGV;
} elsif ($arg eq "-s") {
 $stat = shift @ARGV;
} elsif ($arg eq "-o") {
 $csv = shift @ARGV;
} else {
 die "$arg: invalid argument\n";
}
defined $input && defined $csv && defined $stat || die "You should def
+ine -i, -o and -s!\n";

You can also use 5.010 and process arguments in "switch-case" style.

[monsoon]

When you parse the options manually, you'll also have to manually deal with multiple single letter options bundled into one argument. Something like -abc - that's 3 switches "a", "b" and "c". In fact "c" can even have an argument. You don't have to worry about any of this stuff with Getopt::Std.

[Anonymous Monk]

Could you explain in detail how this works exactly? Thank you

[aitap]

This can work because there is an array called @ARGV, which contains all the command line arguments passed to the perl script (not to the perl itself). See perlvar for more.

`shift` removes and returns the first element of this array, until none are left (when array is empty, it returns undef), so this `while` loop checks all the command line arguments from left to right (additional `shift`s inside the loop are used to get the parameter next to being processed now). See shift for more.