AckMate is a TextMate plugin for running Ack in a Cocoa window.
AquaLess is a text pager for Mac OS X. It allows you to browse plain text files and -- more importantly -- text output from Unix command line tools. AquaLess is a Cocoa replacement for the less command, which is constrained to the terminal window. AquaLess opens a separate window for each text, so you can keep working in the terminal while you read.
Badia PageFrame allows you to print a frame around the page or spread. You can specify the width, color and style of the frame before printing.
CaraCaraC is a characters meter. After counting a text, it displays the total number of characters (including or not including ponctuation marks and unprintable characters) and the number of different characters.
(commercial) CopyPaste is a digital hub for clipboard material and many other kinds of data. It is easy to use, saves time and allows you to do less and accomplish more.
Data Mining was developed to find the number of Hits (string occurrences) within a large text.
Differences Examiner allows you to compare text files and display their differences. It shows you the differences by displaying identical, modified and missing lines in color. It accepts any kind of text file such as plain text or source code.
E Pluribus Unum
E Pluribus Unum rejoins segmented files, such as files frequently posted on newsgroups. Simply dragīnīdrop your files onto the app and hit the "merge" button
Grep assists in the searching of large text files. It is highly optimized and has support for textual and regular expression (PCRE) matching with threaded loading and matching to keep UI responsive at all times.
NFOViewer is a viewer for the .nfo informational files with ASCII art often found in .zip or .rar files originating from PC users.
RegExhibit shows you what your regular expressions match as you type on a sample text you provide. You can set the colour RegExhibit uses for this, and whether it should underline matches and captures. It also provides full details on successful matches.
Screen Sieve is a tool that lets you search the contents of the currently active window at any time. It highlights all occurrences of characters, words and phrases as you type, without requiring modifications to applications. Putting Mac OS X' built-in support for Accessibility to good use, Screen Sieve works with any application that supports the Accessibility APIs.
Shindler is a utility which helps Mac users to track any folder, internal or external HD and USB flash drives. Shindler can be very useful to track a folder (also an HD), which can be read offline. The text file can be sent to anyone who needs to search for a file or a set of files on your HD #not needing physical access.
(shareware) Stripper is a drag-and-drop utility for performing simple operations on text files. Stripper began life in the early 1980s on the IBM PC. Its original purpose was to convert WordStar files to 7-bit ASCII. It "stripped the high bits", hence its name.
TextChanger is a tool for making batch changes to the creator type of text files; you can also use it to "zap" (remove) the resource forks of text files at the same time.
Tidy Service can be used to clean up HTML markup in any application that supports services by selecting the markup in question and choosing one of Tidy menu items from the Services menu.
WordPod converts an e-book into a set of files which can be read on any modern iPod (one with a dock connector).