How to make use of UUIDGEN of unix in perl script - perl

Question

I am trying to generate a unique number using uuidgen (of unix). The generated unique number should get stored in a variable. When i am doing it in a function , I am facing errors.
Can anyone let me know how to make use of uuidgen script in perl.
#!/usr/bin/perl
sub function_uuidgen
{
my myuuid;
system(`export myuuid=uuidgen`);
print "\n unique id is : $myuuid";
# I need not to export the variable, I just need to unique number generated by UUID GENERATOR in a variable.
}
int main
{
print "\n I am in main function";
&function_uuidgen;
}
I am facing the below error when I am running uuidgen as mentioned below. Can anybody help me out with exporting the JAVA VARIABLE in perl ? How to export the path variable,in case if this error is related to that.
Error :
/bin/java: uuidgen 1: not found
Code :
sub function_uuidgen
{
my $myuuid = qx(uuidgen);
chomp $myuuid;
print "\n unique id is : $myuuid";
# I need to export the variable, as it is giving me error without exporting.
}
int main
{
print "\n I am in main function";
function_uuidgen();
}

Answer 1

You're mixing up C and Perl here.
As far as I know you can't access exportet system variables that way from perl (correct me if I am wrong. I don't have much knowledge of linux system variables).
A way to generate UUID's would be the Data::GUID Module from CPAN
use strict;
use warnings;
use Data::GUID qw( guid_string );
my $guid = guid_string();
print "$guid\n";
Also Perl doesn't have an int main function. Your code starts at the top and runs down to the bottom. Of course this gets a bit different if you create an object orientated module.

Answer 2

If you for some reason can't use Data::GUID, this is a way to use the output of uuidgen (note the backticks):
#!/usr/bin/perl
use strict;
use warnings;
my $uuid=`uuidgen`;
chomp $uuid;
print "$uuid\n";
Example output:
$ ./hep.pl
fe82c4f6-a1f2-4242-ab45-853780931927
$
Also, using & before function calls went out of fashion many years ago :-)

Answer 3

Without knowing anything about uuidgen: You could just
my $perlVar = `uuidgen`;
within perl.
Assuming calling uuidgen in your console returns the number you are looking for.

Answer 4

export is a shell command that adds a variable and value to its environment block. The environment block is private to a process, but (by default) copied to a child process. You appear to be thinking it is some sort of global area - it is not.
So, all you would be doing is adding a value to the shell's environment block, not your own! (That's the shell created by system(), not the one you were running from). Placing the export inside back-ticks is strange, if not wrong.
Easier to use:
my $myuuid = qx(uuidgen);
chomp $myuuid;
Notice I am using qx instead of back-ticks `` because they can be confusing (back-ticks are deprecated in UNIX shells as well).
To run the subroutine, loose the C style int main:
print "\n I am in ", __PACKAGE__, "package\n";
function_uuidgen();
The leading & on a subroutine call has side-effects that you probably don't need.