The file is actually created by your editor, not by bash (unless you're doing a
touch foo.pl or similar and then editing the empty file), so the answer would be editor-specific. Most likely, though, the editor (like bash) will use a single umask setting which is applied to determine the initial permissions of all new files, regardless of their type.
However, when copying a file, bash copies its permissions as well... My personal workaround to avoid lots of chmodding is to cp foo bar; vi bar (where foo happens to be a Perl program/module - the .pl is strictly optional) so that I'm editing an existing file which already has the right permissions rather than creating a new one with the editor.
