file handler in perl not working in subroutine - perl

Question

#!/bin/perl
open( $WP, ">/home/Octa.txt" );
# Subroutine test
sub test {
$var1 = shift;
print $WP "TESTING\n";
}
# Subroutine func
sub func {
$var = shift;
if ( $var eq "Ocat" ) {
print $WP "String found\n";
test($var);
}
else {
print $WP "String not found\n";
}
}
$var3 = "Octa";
func($var3);
The issue is that the code is not able to write anything within the test subroutine or within the if condition of the 'funcsubroutine, but it prints in theelse` part of the 'func' subroutine.

Answer 1

First off, there is a typo -- you test $var against "Ocat", while Octa is intended.
So the test subroutine never gets called and only String not found is printed.
With that corrected and with the output file in a user writeable location, your program works.
However, some improvements are necessary.
use warnings;
use strict;
my $file = 'Octa.txt';
open my $WP, '>', $file or die "Can't open $file: $!";
my $var3 = "Octa";
func($WP, $var3);
#Subroutine test
sub test{
my ($fh, $var1) = #_;
print $fh "TESTING\n";
}
#Subroutine func
sub func{
my ($fh, $var) = #_;
if ($var eq "Octa"){
print $fh "String found\n";
test($fh, $var);
}
else {
print $fh "String not found\n";
}
}
I've changed the output file name since a user normally may not write to /home directory.
Comments
It is much better to use the three-argument form of open, in which case you get a lexical file handle which can be passed around nicely and is scoped. This question is a good example of how a global file handle can make things confusing, to say the least.
Always check the open call. For one thing, can you really write to /home directory?
Please always start programs with use warnings; and use strict;
There is another possibility for failure, which brings together practices in the comments above.
A file in /home normally isn't writeable by a user, in which case the posted program cannot work.
But without a check of open (which will fail) and without use warnings (which would be printed every time we touch the invalid $WH filehandle) we will not see any of these errors; instead, the program will quietly run and complete but it won't write the output file.