**ed**

ed is the standard text editor.

ed has two modes: command and input.  By default it is in command mode.  Use //i// or //a// to insert or append text and when finished input a //.// on a line all by itself to return to command mode.

**A summary of ed commands**

||command||description||
||a||append text to the buffer||
||i||insert text at the current line in the buffer||
||p||print the current line - try //1p// to print the first line||
||q||quit ed - to quit without saving, type //q!//||
||s||search/replace - try s/old/new||
||w||write out the buffer to disk - //w filename//||
||.||return to command mode from //a//ppend or //i//nput mode||

If you have made an error, ed will only respond with //?//