8 Surprising Ways to Use the ‘!’ Operator in Linux Commands

1. Run a command by its history number

After listing the command history with history, you can execute a previous command by prefixing its line number with !, e.g., !58 runs the command on line 58 of the history.

linuxmi@linuxmi:~/www.linuxmi.com$ history

$ !58

The exact number varies per session.

2. Execute a previously run command using negative indexing

The !-n syntax refers to the nth most recent command, where -1 is the last command, -2 the one before, and so on.

$ history</code><code>$ !-3</code><code>$ !-6</code><code>$ !-10

3. Pass the previous command’s arguments to a new command

Use !$ to reuse the last argument of the preceding command. For example, after ls /home/linuxmi/snap, you can run ls -l !$ to list the same directory in long format.

$ ls /home/linuxmi/snap

$ ls -l !$

4. Work with two or more parameters

When a command has multiple arguments, !^ expands to the first argument, !cmd:2 expands to the second argument of cmd, and !* expands to all arguments.

linuxmi@linuxmi ~/www.linuxmi.com% touch /home/linuxmi/linuxmi.go

linuxmi@linuxmi ~/www.linuxmi.com% cp /home/linuxmi/linuxmi.go /home/linuxmi/go

% echo "First argument is: !^"

First argument is: /home/linuxmi/linuxmi.go

% echo "Second argument is: !cp:2"

Second argument is: /home/linuxmi/go

5. Run the most recent command matching a keyword

Prefix a command with ! followed by a keyword to repeat the last command that started with that keyword.

$ ls /home > /dev/null      [Command 1]</code><code>$ ls -l /home/linuxmi/linuxmi > /dev/null   [Command 2]</code><code>$ ls -la /home/linuxmi/linuxmi.com > /dev/null   [Command 3]</code><code>$ ls -lA /usr/bin > /dev/null   [Command 4]

$ ! ls      # repeats Command 1</code><code>$ ! ls -l   # repeats Command 2</code><code>$ ! ls -la  # repeats Command 3</code><code>$ ! ls -lA  # repeats Command 4

6. Repeat the last command with !!

The double‑bang shortcut expands to the previous command. It can be combined with su -c "!!" root to re‑execute the last command as root.

$ ip addr show | grep inet | grep -v 'inet6' | grep -v '127.0.0.1' | awk '{print $2}' | cut -f1 -d/

$ ip addr show | grep inet | grep -v 'inet6' | grep -v '127.0.0.1' | awk '{print $2}' | cut -f1 -d/ > ip.txt

su -c "!!" root

7. Delete all files except a specific one

Using the extended glob !(pattern) with rm removes everything that does not match the pattern.

$ rm !(important_file.txt)

$ rm !(*.pdf)

8. Check whether a directory exists

Combine the test [ ! -d /path ] with logical AND ( &&) and OR ( ||) to print messages or take actions based on the directory’s presence.

$ [ ! -d /home/linuxmi/linuxmi.com ] && printf '
no such /home/linuxmi/linuxmi.com directory exist
' || printf '
/home/linuxmi/linuxmi.com directory exist
'

$ [ ! -d /home/linuxmi/linuxmi.com ] && exit

[ ! -d /home/linuxmi/linuxmi.com ] && mkdir /home/linuxmi/linuxmi.com

The article concludes by inviting readers to share any additional “!” tricks they know.