Linux in a Nutshell, Fourth 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. The following flags can be specified:

n

Replace nth instance of / pattern / on each addressed line. n is any number in the range 1 to 512; the default is 1.

g

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

I

Case insensitive match. This flag is available only on GNU versions of sed.

p

Print the line if a successful substitution is done. If several successful substitutions are done, multiple copies of the line will be printed.

w file

Write the line to a file if a replacement was done.

Examples

Here are some short, commented scripts:

                  # Change third and fourth quote to ( and ):
/function/{
                  s/"/(/3
                  s/"/)/4
                  }

                  # Remove all quotes on a given line:
/Title/s/"//g

                  # Remove first colon or all quotes; print resulting lines:
s/://p
                  s/"//gp

                  # Change first "if" but leave "ifdef" alone:
/ifdef/!s/if/   if/