[Chapter 4] 4.5 Command History

4.5 Command History

The Korn shell lets you display or modify previous commands. Commands in the history list can be modified using:

Line-edit mode
The fc and hist commands

Line-edit mode emulates many features of the vi and emacs editors. The history list is treated like a file. When the editor is invoked, you type editing keystrokes to move to the command line you want to execute. You can also change the line before executing it. When you're ready to issue the command, press the Return key.

Line-edit mode can be started in several ways. For example, these are equivalent:

$ VISUAL=vi


$ EDITOR=vi


$ set -o vi

	Overrides value of VISUAL or EDITOR

Note that vi starts in input mode; to type a vi command, press the Escape key first.

4.5.1.1 Common editing keystrokes

vi	emacs	Result
`k`	`CTRL-p`	Get previous command.
`j`	`CTRL-n`	Get next command.
`/` string	`CTRL-r` string	Get previous command containing string .
`h`	`CTRL-b`	Move back one character.
`l`	`CTRL-f`	Move forward one character.
`b`	`ESC-b`	Move back one word.
`w`	`ESC-f`	Move forward one word.
`X`	`DEL`	Delete previous character.
`x`	`CTRL-d`	Delete character under cursor.
`dw`	`ESC-d`	Delete word forward.
`db`	`ESC-h`	Delete word backward.
`xp`	`CTRL-t`	Transpose two characters.

4.5.2 The fc and hist Commands

Use fc -l to list history commands and fc -e to edit them. See the entry under "Built-in Commands" for more information.

In ksh93 , the fc command has been renamed hist , and alias fc=hist is predefined.

4.5.2.1 Examples

$ history

		List the last 16 commands
	
$ fc -l 20 30

	List commands 20 through 30

$ fc -l -5

	List the last five commands

$ fc -l cat

	List the last command beginning with cat

$ fc -ln 5 > doit

	Save command 5 to file doit.
	
$ fc -e vi 5 20

	Edit commands 5 through 20 using vi

$ fc -e emacs

	Edit previous command using emacs

$ r

		Reexecute previous command

$ r cat

		Reexecute last cat command

$ r doc=Doc

	Substitute, then reexecute last command

$ r chap=doc c

	Reexecute last command that begins with c, but change string chap to doc

4.5 Command History

4.5.1 Line-Edit Mode

4.5.1.1 Common editing keystrokes

4.5.2 The fc and hist Commands

4.5.2.1 Examples