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| |
sed commands have the general form:
[address[,address]][!]command [arguments]
sed commands consist of addresses and editing commands. commands consist of a single letter or symbol; they are described later, alphabetically and by group. Some commands accept or expect arguments. Examples of 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 in the next section.
A sed command can specify zero, one, or two addresses. An address can be a line number, an increment given as a starting line number and a step amount separated by a tilde (~), the symbol $ (for last line), or a regular expression enclosed in slashes (/pattern/). Regular expressions are described in Chapter 9. Additionally, \n can be used to match any newline in the pattern space (resulting from the N command) but not the newline at the end of the pattern space.
|
If the command specifies |
Then the command is applied to |
|---|---|
|
No address |
Each input line. |
|
One address |
Any line matching the address. Some commands (a, i, r, q, and =) accept only one address. |
|
Two comma-separated addresses |
First matching line and all succeeding lines up to and including a line matching the second address. |
|
An address followed by ! |
All lines that do not match the address. |
s/xx/yy/g Substitute on all lines (all occurrences)
/BSD/d Delete lines containing BSD
/^BEGIN/,/^END/p Print all lines between lines that begin with
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
1~2 p Print all odd numbered lines
2~3 d Delete every third line beginning with the second.Braces ({ }) are used in sed to nest one address inside another or to apply multiple commands at the same address:
[/address/[,/address/]]{
command1
command2
}The opening curly brace must end a line, and the closing curly brace must be on a line by itself. Be sure there are no blank spaces after the braces.
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| 12. The sed Editor |  | 12.3. Group Summary of sed Commands |
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