How to Display Command History in Linux

Displaying the Command History

The shell keeps a history of recently entered commands. This history mechanism enables you to view, repeat, or modify previously executed commands.

NOTE: Command history is shared among all Korn shells for a given user.

Using the history Command

The history command displays previously-executed commands. By default, the history command displays the last 16 commands to the standard output. The syntax for the history command is:

$ history option

To display previously executed commands, perform the following command:

$ history
...
87 date
88 cd /etc
89 touch dat1 dat2
90 ps -ef
91 history

The history command is an alias built into the Korn shell that enables you to display previously-executed commands.

NOTE: Your output varies based on the commands recorded in your .sh_history ﬁle. The output can include commands from multiple windows.

The numbers on the left are command numbers. You can use the command numbers to instruct the shell to re-execute a particular command line. To display the command history without line numbers, perform the following command:

$ history -n
 ...
 date
 cd /etc
 touch dat1 dat2
 ps -ef
 history

To display the current command and the four commands preceding it, perform the following command:

$ history -4
 ...
 107 date
 108 cd /etc
 109 touch dat1 dat2
 110 ps -ef
 111 history

To display the history list in reverse order, perform the following command:

$ history -r
111 history
110 ps -ef
109 touch dat1 dat2
108 cd /etc
107 date
...

To display the most recent cd command to the most recent date command, perform the following command:

$ history cd ls
31 cd
32 man lp
33 date
... (output truncated)

NOTE: The Korn shell stores command history in a ﬁle speciﬁed by the HISTFILE variable. The default ﬁle is the ~/.sh_history ﬁle. You can use the HISTSIZE variable to specify the number of commands to store in this buffer. If this variable is not set, then the shell stores the most recent 128 commands.

Using the r Command (in ksh shell)

The r command is an alias built into the Korn shell that enables you to repeat a command. To repeat the cal command by using the r command, perform the following command:

$ cal
December 2004
S  M  Tu  W  Th  F  S
          1  2  3  4
5  6  7  8  9 10  11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

$ r
cal
December 2004
S  M  Tu  W Th  F  S
          1  2  3  4
5  6  7   8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

To re-execute a command by line number, use the r command followed by the respective line number. For example:

$ history
155 history
156 cat dante
157 history
158 date
159 cal
160 ls
161 cd

$ r 160
( output omitted )

You can also use the r command to re-execute a command beginning with a particular character, or string of characters. To rerun the most recent occurrence of a command that begins with the letter “c,” perform the following command:

$ r c
$ cd /etc

To rerun the most recent occurrence of the ps command, perform the following command:

$ r ps
ps -ef

You can use the r command to repeat a previous command, perform a simple edit, and perform the modiﬁed command. For example, to repeat the most recent occurrence of a command beginning with the letter “c,” replace dir1 with dir2, and perform the modiﬁed command as follows:

$ history
 ...
 100 cd
 101 cat dante
 102 ls
 103 cd ~/dir1
 104 history

$ r c
cd ~/dir1
$ r dir1=dir2
cd ~/dir2

Editing and Rerunning Previously Executed Commands

You can edit previously-executed commands and rerun these commands using a shell in-line editor. Use the vi editor to turn on and enable the shell history editing feature with one of the following commands:

$ set -o vi

$ export EDITOR=/bin/vi

$ export VISUAL=/bin/vi

NOTE: All three commands turn on vi command-line editing for the shell. To verify this, you can use the set -o command.

You can access command in the history buffer, edit the command with the vi editor, and execute the modiﬁed command by following these steps:

1. Verify that the built-in vi editor is enabled.

$ set -o | grep -w vi
vi          on

2. Type the history command to view the command history list.

$ history

3. Press Escape to access the command history list. Use the following keyboard keys to move the cursor through the command history.

k – Moves the cursor up one line at a time
j – Moves the cursor down one line at a time
l – Moves the cursor to the right
h – Moves the cursor to the left

NOTE: You cannot use the arrow keys to move the cursor within the command history.

4. Use the vi commands to edit any previously executed command.

5. To perform a modiﬁed command, press Return.

File Name Completion

To invoke ﬁle name completion, type the ls command followed by one or more characters of a ﬁle name, and then press the following keys in sequential order: Escape (Esc) and backslash (\).

NOTE: The key sequence presented previously applies only to the vi mode of command-line editing.

If the shell ﬁnds a ﬁle name beginning with the speciﬁed characters, it prints the complete ﬁle name or ﬁle names to the command line. For example, to expand a ﬁle name beginning with the characters de in the /usr directory:

$ cd /usr
$ ls de      Press Esc and \

The shell completes the remainder of the ﬁle name, displaying:

$ ls demo/

You can request the shell to present all the possible alternatives of a partial ﬁle name from which you could then select. This action is invoked by pressing the following keys sequentially: Escape (Esc) and the equal (=) key.

To request that the shell present all ﬁle names beginning with the letter “g” in the/etc directory, type:

$ cd /etc
$ cat g Press Esc, press the = key1) gconf/
2) getty
3) gimp/
4) gnome-vfs-2.0/
5) gnome-vfs-mime-magic
6) gnopernicus-1.0/
7) group
8) grpck
9) gss/
10) gtk-2.0/
11) gtk/
$ cat g

The cursor is positioned on top of the letter “g” at this point.