use strict;
use warnings;
use Cwd;
my $dir = shift;
chdir $dir or die "Couldn't chdir $dir: $!\n";
print "OK, in ". getcwd . "\n";

##</code><code>##

# ./change.pl Downloads/
OK, in /home/Random/Downloads
# ./perl change.pl foo
Couldn't chdir foo: No such file or directory
# ./mkdir bar
# ./chmod 000 bar
# ./perl change.pl bar
Couldn't chdir bar: Permission denied