Install CPAN modules only if not yet present

Posted on 2011-06-16 09:58:28
by Geert Vandeweyer

Loading Content

Install CPAN modules only if not yet present

Posted on 2011-06-16 09:58:28
by Geert Vandeweyer

I needed a way to check if a certain CPAN module is present on the system/path, before installing the module again. This way I wanted to prevent that newer versions of mdoles were installed by an installer I created for some application. 

The following script takes a module name as argument and tries to load it. If it doesn't exists, it will be installed from CPAN. If it is already present on the system, the option is presented to reinstall/update. 

Usage: 

geert@ubuntu: sudo getCpanModules.pl "HTTP::Cookies"

Code:

#!/bin/perl
## get command line arg
my $module = $ARGV[0];
## exit if no module provided.
if ($module eq '') {
	print "No Module name provided. Installer will exit.\n";
	exit();
}
## try to load
eval
{
  ( my $toload = "$module.pm") =~ s/::/\//g;
  require $toload;
  $module->import();
};
## check result
if ($@) {
	print "Installing $module from CPAN:\n";
	system("perl -MCPAN -e 'install $module'");
}
else {	
	print "\n  Module $module exists. Do we need to upgrade/reinstall? y|[n] : ";
	$answer = <STDIN>;
	chomp($answer);
	if ($answer =~ m/y/i) {
		print "  Reinstalling $module from CPAN:\n";
		system("perl -MCPAN -e 'install $module'");
	}
	else {
		print "\tNot updating $module\n";
	}	
}

Batch, CPAN, Installation, Perl