[Chapter 4] 4.5 Command History

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Previous: 4.4 Arithmetic Expressions

Chapter 4
The Bourne Shell and Korn Shell

Next: 4.6 Built-in Commands (Bourne and Korn Shell)

4.5 Command History

The Korn shell lets you display or modify previous commands. This is similar to the C shell's history mechanism. Commands in the history list can be modified using:

Line-edit mode
The fc command

4.5.1 Line-edit Mode

Line-edit mode lets you emulate many features of the vi or emacs editor. 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 RETURN.

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 ESCAPE 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 one character.
dw	ESC-d	Delete word forward.
db	ESC-h	Delete word back.
xp	CTRL-t	Transpose two characters.

4.5.2 The fc Command

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

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

	
Re-execute previous command.

$ 

r cat

	
Re-execute last
 cat 
command.


$
 

r doc=Doc

	
Substitute, then re-execute last command.

$ 

r chap=doc c

	
Re-execute last command that begins with
 c,
	
but change string
 chap 
to
 doc.


4.4 Arithmetic Expressions		4.6 Built-in Commands (Bourne and Korn Shell)

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