Why do I have to explicitly add perl before the script for getops to run properly?

Question

When i run my script like so:

C:\>perl script.pl -f file

It works fine. But, if I just do:

C:\>script.pl -f file

then I don't get any errors but getopts doesn't assign anything to $opt_f

This works just fine on perl 5.8 Windows XP, but it doesn't work on perl 5.12 on Windows 7. There aren't any other versions of perl installed (its a new OS build).

Code:

use Getopt::Std;
our ($opt_f);
getopts('f:');
print "input file is: $opt_f \n";
print "$0\n

Run with:

C:\> perl get.pl -f sadf
input file is: sadf
get.pl

Run without:

C:\>get.pl -f sadf
input file is:

Nothing!

EDIT: fixed and this question was a repeat... http://stackoverflow.com/questions/1695188/how-do-i-make-perl-scripts-recognize-parameters-in-the-win32-cmd-console

The OP of that post figured it out.
I had to do the same but also recreate the assoc in the gui (in addition to in the reg and on the command line with ftype.)

Answer 1

When you invoke your code as perl script.pl -f file, you are explicitly running the perl executable and passing it a filename and options to parse. But when you invoke it as script.pl -f file, you are asking your login shell to run the file, which it will parse as a shell script in the absence of any other information -- this is not what you want, as your file is not a bash script, but a perl script!

Normally such information (what program to use to parse the script) is given in what is called a shebang line. If you add this to the top of your script, it should run properly:

#!/usr/bin/perl

(or perhaps #!/bin/env perl, if you want the env program to find perl in your $PATH for you).

Answer 2

What are Perl scripts associated with (.pl extension to be precise) on the Windows7 system where the "script.pl" call doesn't work?

Also, could you please try running (with and without "perl " prefix):

use Data::Dumper; print Data::Dumper->Dump([$*, $0, $1])

Answer 3

First, look at:

C:\> assoc .pl
.pl=Perl

Take the string on the RHS, and invoke:

C:\> ftype Perl
Perl="C:\opt\Perl\bin\perl.exe" "%1" %*

Make sure %* is there.

If not, run a cmd.exe shell as administrator, and invoke

C:\> ftype Perl=perl.exe %1 %*

See also ftype /?.

Answer 4

fixed and this question was a repeat... http://stackoverflow.com/questions/1695188/how-do-i-make-perl-scripts-recognize-parameters-in-the-win32-cmd-console

The OP of that post figured it out. I had to do the same but also recreate the assoc in the gui (in addition to in the reg and on the command line with ftype.)

Thanks everyone for your help!