Unix in a Nutshell, 4th Edition

Name

s

Synopsis

[address1[,address2]]s/pattern/replacement/[flags]

Substitute replacement for pattern on each addressed line. If pattern addresses are used, the pattern // represents the last pattern address specified. Any delimiter may be used. Use \ within pattern or replacement to escape the delimiter. The following flags can be specified (those marked with a † are specific to GNU sed ):

n

Replace n th instance of pattern on each addressed line. n is any number in the range 1 to 512, and the default is 1.

e †

If the substitution was made, execute the contents of the pattern space as a shell command and replace the pattern space with the results.

g

Replace all instances of pattern on each addressed line, not just the first instance.

i or I †

Do a case-insensitive regular expression match.

m or M †

Allow ^ and $ to match around a newline embedded in the pattern space.

p

Print the line if the substitution is successful. If several successive substitutions are successful, sed prints multiple copies of the line.

w file

Write the line to file if a replacement was done. In Unix sed, a maximum of 10 different files can be opened.

GNU sed allows you to use the special filenames /dev/stdout and /dev/stderr to write to standard output or standard error, respectively.

Within the replacement, GNU sed accepts special escape sequences, with the following meanings:

\L	Lowercase the replacement text until a terminating \E or \U.
\l	Lowercase the following character only.
\U	Uppercase the replacement ...