UNIX / Linux : Examples of bash history command to repeat last commands

One of the extensively used command in UNIX world is the history command. Every flavor of UNIX has the history command. The bash shell stores a history of commands entered, which can be used to repeat commands by using the history command. By default, it’ll show the previous 1000 commands that were used.

Here’s a sample output of the command history:

# history
    1  uname -a
    2  clear
    3  ssh root@192.168.1.50
    4  exit
    5  ls
    6  clear
    7  echo "Hello"
    ........

The bash history mechanism supports a variety of advanced ways of retrieving commands from the history list. Below are some of the ways to use the bash history command :

1. Listing last n commands used

By default, history command shows the last 1000 commands used. If you want to list only last few commands fired by the user use “history n”. For example, to display last 5 commands fired :

# history 5
  504  uname -a
  505  who am i
  506  date
  507  echo "Hi"
  508  history 5

2. Repeating last command

To repeat the last command executed :

# echo "I am history"
I am history
# !!
echo "I am history"
I am history

3. Repeat last command starting with some character

!char = repeats last command that started with char. For example :

# !uname
uname -a
Linux geeklab 2.6.32-504.el6.x86_64 #1 SMP Tue Sep 16 01:56:35 EDT 2014 x86_64 x86_64 x86_64 GNU/Linux

4. Repeat last command by its number

!num = repeats a command by its number in history output. For example :

# !1010
ls -lrth
total 197M
-rw-r--r-- 1 root root 512K May 25  2015 file1
drwxr-xr-x 2 root root 4.0K Jun  1  2016 dir1

5. Repeat last command that contains some character

!?command = repeats last command that contains (as opposed to started with [!char]) command. Example :

# echo "I am legend"
I am legend
# !?legend
echo "I am legend"
I am legend

6. Repeat the nth last command

!-n = repeats a command entered n commands back

# !-3
uname -a
Linux VMAX3Linux 2.6.32-358.el6.x86_64 #1 SMP Tue Jan 29 11:47:41 EST 2013 x86_64 x86_64 x86_64 GNU/Linux

7. Searching for a command in history and executing it

Ctrl-r = search for a command in command history and execute it once you find a match.

#
(reverse-i-search)`uname': uname -a