How to pass parameters to Perl module from Bash shell script, and retrieve values?-CodePudding

A function in Perl module takes 3 parameters. The value of the first parameter will determine the values of the other parameters and return them back to the caller. It is defined like this:

package MyModule;

sub MyFunction
{
   my $var_0 = $_[0];
   my $var_1;
   my $var_2;

   if ($var_0 =~ /WA/) {
      $var_1 = "Olympia";
      $var_2 = "Population is 53,000";  
   }
   elsif ($var_0 =~ /OR/) {
      $var_1 = "Salem";
      $var_2 = "Population is 172,000"; 
   }  
  
  $_[1] = $var_1;
  $_[2] = $var_2; 

 return 0; # no error
}

Calling this function from the bash shell script:

VAL=`perl -I. -MMyModule -e 'print MyModule::MyFunction("WA")'`
echo $VAL

Problem: The VAL only stores the value of the last variable or $var_2.

Question: How can I retrieve the value from both $var_1 and $var_2, for use later in this bash script? ( assuming code from perl function can not be modified). Thanks for your help.

CodePudding user response：

Your function is modifying the value of its arguments #2 #3 so you may pass variables to it and print them:

perl -l -I. -MMyModule -e 'MyModule::MyFunction("WA",$a,$b); print $a; print $b;'

CodePudding user response：

You print the value returned by MyFunction, which is 0. So that's why 0 is assigned to $VAL.

You should return the value instead of assigning them to the $_[1] and $_[2].

package MyModule;

use Exporter qw( import );

our @EXPORT = qw( MyFunction );

sub MyFunction {
   my $var_0 = shift;

   if ($var_0 =~ /WA/) {
      return "Olympia", "Population is 53,000";  
   }
   elsif ($var_0 =~ /OR/) {
      return "Salem", "Population is 172,000"; 
   }  
}

perl -I. -MMyModule -le'print join " ", MyFunction( "WA" )'