It offers different functions based on regular expressions. One of them, find and replace, is very convenient to edit data files stored in plain text. TextWrangler also allows you to compare differences in files and merge files together. In addition, it supports Perl regular expressions.
TextWrangler integrates with Xcode as an external editor and supports AppleScript. It includes a Shebang! menu which provides direct access to UNIX scripting environments. Files made with TextWrangler can be saved in the end file formats for Mac, Unix, DOS and Unicode.
For Mac 10.4 or later. Mac OS X Panther (10.3.5) users can download TextWrangler 2.1.3.