I interpret the question as : I only want to run this script if it is invoked from the symlinked folder.

Use Path::Tiny if you want to stay portable (as posted earlier).

Check -l, readlink, and Cwd::abs_path to fill your needs.

#!perl

use Cwd qw( getcwd abs_path );

my ($DIR, $CMD) = $0 =~ m{^(.*)/([^/]+)$};
! $CMD && ! -d $DIR and ($DIR, $CMD) = (getcwd, $DIR); # "." in $PATH 
+and script invoked without ./
-l $DIR or die "$DIR is not the symlinked folder. Running like this is
+ dangerous!\n";

say "Current dir    : ", getcwd;
say "Invoking folder: ", $DIR;
say "Symlink        : ", readlink $DIR;
say "Abs path:      : ", abs_path $DIR;
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$ mkdir -p tmp/test-a
$ ln -s test-a tmp/test
$ ln -s tmp/test test
$ vi tmp/test/test.pl
-- paste above code and save
$ perl test/test.pl
Current dir    : /home/tux
Invoking folder: test
Symlink        : tmp/test
Abs path:      : /home/tux/tmp/test-a
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