Unix Power Tools, 3rd Edition

Chapter 21. You Can’t Quite Call This Editing

And Why Not?

Summary Box

There are many specialized forms of editing that happen frequently enough that they sometimes want to be saved into a script. Examples of this kind of thing include:

• fmt (Section 21.2) and related scripts (Section 21.3) for reformatting jagged lines into neat paragraphs

• recomment (Section 21.4), a script for reformatting comment blocks within programs and scripts

• behead (Section 21.5), a script for removing the headers from mail and news messages

• center (Section 21.8), a script for centering lines of text in a file

In addition, there are a number of programs that provide some useful ways of modifying files but that you don’t normally think of as editors:

• split (Section 21.9) and csplit (Section 21.10) let you split a big file into smaller pieces.

• tr (Section 21.11) lets you substitute one character for another — including non-printing characters that you specify by their octal values.

• dd (Section 21.6, Section 21.13) lets you perform various data conversions on a file.

• cut (Section 21.14) lets you cut columns or fields out of a file, and paste (Section 21.18) lets you put them back, perhaps in a different order.

This chapter covers all that and more.

— TOR

Neatening Text with fmt

One of the problems with fold is that it breaks text at an arbitrary column position — even if that position happens to be in the middle of a word. It’s a pretty primitive utility, designed to keep long lines from printing off the edge of a line ...