10.3 Syntax of sed Commands
sed commands have the general form:
[address [
,address ]][!]command [arguments ]
sed copies each line of input into the pattern space. sed instructions consist of addresses and editing commands . If the address of the command matches the line in the pattern space, the command is applied to that line. If a command has no address, it is applied to each input line. If a command changes the contents of the pattern space, subsequent commands and addresses are applied to the current line in the pattern space, not the original input line.
commands
consist of a single letter or symbol; they are described later, alphabetically and by group. arguments
include the label supplied to b
or t
, the filename supplied to r
or w
, and the substitution flags for s
. addresses
are described below.
10.3.1 Pattern Addressing
A sed
command can specify zero, one, or two addresses. An address can be a line number, the symbol $
(for last line), or a regular expression enclosed in slashes (/pattern
/). Regular expressions are described in Chapter 6, Pattern Matching
. Additionally, \n
matches any newline in the pattern space (resulting from the N
command), but not the newline at the end of the pattern space.
10.3.2 Examples
s/xx/yy/g
|
Substitute on all lines (all occurrences). |
/BSD/d
|
Delete lines containing BSD
. |
/^BEGIN/,/^END/p
|
Print between BEGIN
and END
, inclusive. |
/SAVE/!d
|
Delete any line that doesn't contain SAVE
. |
/BEGIN/,/END/!s/xx/yy/g
|
Substitute on all lines, except between BEGIN
and END
. |
Braces ({}
) are used in sed
to nest one address inside another or to apply multiple commands at the same address.
[/pattern
/[,/pattern
/]]{
command1
command2
}
The opening curly brace must end its line, and the closing curly brace must be on a line by itself. Be sure there are no spaces after the braces.
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| 10.2 Command-Line Syntax | 
|
10.4 Group Summary of sed Commands |
