sed ­ the Stream Editor

This uses editing commands that have the same form as the line editor ed and the visual editor, vi. One application of sed is "search and replace" operations on whole files, or sets of files. The general form of a sed command is

sed 'list of editing commands' filename(s)

Example

To change the word hedge in a file to wart the substitute option, s, can be used:

sed 's/hedge/wart/g' verse1

The g at the end of the editing commands means "global", i.e. change all occurrences on that line. This command writes the resulting lines to the screen. To write to a file, redirect:

sed 's/hedge/wart/g' verse1 > verse1.wart

Regular expressions as defined for grep, can also be used with sed. Quite complex scanning can be performed by sed, with the constraint that only a single pass through the input file is made.

Help: for more information see sed(1), vi(1) and ed(1).