Use the File::Basename module:

use strict;
use File::Basename;

while (<DATA>) {
  chomp;
  my $dir = dirname $_;
  my $file = basename $_;
  print "I am '$file' in '$dir'.\n";
};
__DATA__
/proj/home/me/asdf.pl
asdf1.pl
foo/asdf.pl
[download]

Another alternative might be the FindBin module:

use strict;
use FindBin;

print "I am in '$FindBin::Bin'.";
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