Unix Command Line Editing

Unix Command-Line Editing Summary

Here is a table that summarizes how to start using Unix command-line editing. Command-line editing can be helpful whenever the number of keystrokes it takes you to edit and re-run a command is less than the number of keystrokes to re-type it. It is very helpful any time you are running commands repeatedly, and can signifcantly reduce the time and effort it takes to complete your Unix projects.

Part 1.   Re-Running a command line depends on which shell you are running.

How to Re-Run commands: ksh bash

    re-run the last command r !!

    re-run by <command number>, say: 90 r <number>        e.g.,   r   90 !<number>     e.g.,    !90

    re-run by <string>, e.g., grep
    finds most recent command line that starts-with <string>. r   <string>        e.g.,    r   grep !<string>      e.g.,   !grep

Part 2: Editing a command line depends on which style of editing you are using.
(Just a few of the many possible commands for editing a line in "vi" and "emacs" are listed.)

Function 'vi' style 'emacs' style

Default for this shell ksh bash

"set" command to switch to it set   -o   vi set   -o   emacs

Finding a command line to Edit:

    enter command line edit mode <esc> always on because we use control characters or escape sequences

    go back a line k ^P

    go forward a line n ^N

    search back for a <string>, e.g., grep
    finds most recent command line that contains <string>. If repeated, finds second most recent occurence. /<string>            e.g.,    /grep ^R<string>        e.g.,   ^Rgrep

Positioning the cursor on the current command line:

    start of line ^      (shift-6) ^A

    end of line $ ^E

    forward (right) one: character <space> ^F

                                        word w <esc>f

    back (left) one:        character h ^B

                                        word b <esc>b

Deleting Text:   delete character under cursor x ^D

                   delete from cursor to end of word dw <esc>d

                                                 to end of line d$ ^K

Adding Text:   insert before cursor i       (press <esc> to end) just type

Executing the edited command line: <enter>   (from anywhere on line) <enter> (from anywhere on line)

Note: the emacs editing control characters are capitalized only for readability. "^A" means: ctrl-a (no shift key).

How to Re-Run commands:	ksh	bash
re-run the last command	r	!!
re-run by <command number>, say: 90	r <number> e.g., r 90	!<number> e.g., !90
re-run by <string>, e.g., grep finds most recent command line that starts-with <string>.	r <string> e.g., r grep	!<string> e.g., !grep

Function	'vi' style	'emacs' style
Default for this shell	ksh	bash
"set" command to switch to it	set -o vi	set -o emacs
Finding a command line to Edit:
enter command line edit mode	<esc>	always on because we use control characters or escape sequences
go back a line	k	^P
go forward a line	n	^N
search back for a <string>, e.g., grep finds most recent command line that contains <string>. If repeated, finds second most recent occurence.	/<string> e.g., /grep	^R<string> e.g., ^Rgrep
Positioning the cursor on the current command line:
start of line	^ (shift-6)	^A
end of line	$	^E
forward (right) one: character	<space>	^F
word	w	<esc>f
back (left) one: character	h	^B
word	b	<esc>b
Deleting Text: delete character under cursor	x	^D
delete from cursor to end of word	dw	<esc>d
to end of line	d$	^K
Adding Text: insert before cursor	i (press <esc> to end)	just type
Executing the edited command line:	<enter> (from anywhere on line)	<enter> (from anywhere on line)