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
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
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.