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... 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

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 2

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 3

If you are using the key word perl fileName.pl -f checkfile (for ex) then you are explicitly invoking the interpreter.

Now, if you want to execute the same command but without the perl key word, then you will need to add the shebang to your code. Check your Windows perl installation. it should be something like this: #!/perl/bin/perl.

What is going to happen now, with this new line, the command line will read the 1st 2 bytes(#!) of the script and figure out that it is a perl script and will know where to find the interpreter and will invoke it(since you provided the path to it). Hence your script will be executed as a perl script.

Answer 4

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 5

fixed and this question was a repeat... 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!

Answer 6

You don't have to add "perl" prefix as..

In order to do so you need to change the PATH environment variable, below is the command to change PATH environment variable

PATH=$PATH:$(pwd)

This will append the current working directory to the list of directories in the PATH environment variable. Once we do this we can now run without "perl" prefix

$ hello.pl

Hello world