Work Efficiently with Command History and Line Editing

In this tutorial, you will build the habit of recalling, editing, and reissuing commands without retyping them. You will work with the history command, incremental reverse search, history expansion operators, and Bash readline shortcuts — all of which are tested on the RHCSA EX200 exam.

What We'll Build

By the end of this tutorial, you will have recalled commands by number, by string prefix, and through reverse search; edited a command on the line before running it; and cleared and navigated the line using keyboard shortcuts. The session will reach this final state:

$ history | tail -5
   96  ls -la /etc
   97  cat /etc/hostname
   98  ls -la /etc
   99  uname -r
  100  history | tail -5

Every technique leaves a trace in the history list — a concrete record that the shell's efficiency tools are working.

Step 1: Display the History List

View the current history list so you have reference numbers to work with.

history

You should see output similar to:

    1  whoami
    2  ls
    3  pwd
    4  uname -r
    5  ls -la /etc
    6  cat /etc/hostname
    7  ls -la /etc

Each line carries a number. Those numbers are what you will use in the next steps to recall specific commands without retyping them.

Step 2: Recall the Most Recent Command with !!

Use !! to repeat the last command you ran — in this case, history itself.

!!

You should see:

history
    1  whoami
    2  ls
    3  pwd
    4  uname -r
    5  ls -la /etc
    ...

Bash prints the expanded command (history) on its own line before running it. This confirmation appears every time a history expansion fires, so you always see what will execute before output appears.

Step 3: Recall a Command by History Number with !n

Recall a specific command by its number. You will rerun the uname -r entry. Look at the number beside uname -r in your history output — substitute that number for 4 if it differs in your session.

!4

You should see:

uname -r
5.14.0-362.el9.x86_64

Bash echoes the expanded command before its output. The kernel version string confirms uname -r ran exactly as it appeared in the history list.

Step 4: Recall a Command by String Prefix with !string

Recall the most recent command that starts with a particular string. You will re-execute the most recent ls command from your history.

!ls

You should see:

ls -la /etc
total 1092
drwxr-xr-x. 136 root root  8192 May  7 09:14 .
...

!ls matched ls -la /etc — the most recent command whose text begins with ls — not the shorter ls typed earlier. Bash always selects the most recent match.

Step 5: Search History Interactively with Ctrl-R

Use incremental reverse search to find a command by typing part of it — without knowing its history number.

Press Ctrl-R at the prompt. The prompt changes to:

(reverse-i-search)`':

Type cat:

(reverse-i-search)`cat': cat /etc/hostname

The most recent command containing cat appears alongside your search string. Press Enter to run it.

You should see:

cat /etc/hostname
rocky-01

You found and ran the command without typing its full text or knowing its history number.

Step 6: Move the Cursor to the Start and End of a Line

Practice cursor navigation on a long command before running it. Type the following command but do not press Enter yet:

ls -la /etc/sysconfig/network-scripts

Press Ctrl-A to jump the cursor to the beginning of the line.

The cursor moves to just before ls:

$ ls -la /etc/sysconfig/network-scripts
  ^
  cursor here

Now press Ctrl-E to jump to the end of the line:

$ ls -la /etc/sysconfig/network-scripts
                                        ^
                                        cursor here

Neither keystroke altered the command text — they only moved the cursor. These two shortcuts let you navigate to any edit point quickly, regardless of command length. Now press Enter to run the command.

You should see:

total 4
drwxr-xr-x. 2 root root   6 Apr 15 08:02 .
drwxr-xr-x. 7 root root 134 Apr 15 08:02 ..

Step 7: Delete from the Cursor to the Beginning of the Line with Ctrl-U

Practice clearing an in-progress command. Type the following but do not press Enter:

ls -la /etc/sysconfig

Press Ctrl-U.

The entire line disappears, returning to a clean prompt:

$

Ctrl-U discards everything from the cursor position back to the start of the line. It is the fastest way to abandon a command you have decided not to run, without reaching for the Backspace key repeatedly.

Step 8: Delete the Previous Word with Ctrl-W

Practice removing one argument at a time. Type the following but do not press Enter:

ls -la /etc/hostname

Press Ctrl-W.

You should see:

$ ls -la 

The argument /etc/hostname is gone, but ls -la remains. Press Ctrl-W again.

You should see:

$ ls 

Each press of Ctrl-W removes exactly one whitespace-delimited word to the left of the cursor. This lets you correct the end of a long command without erasing everything. Press Ctrl-U to clear the line before the next step.

Step 9: Clear the Screen with Ctrl-L

Clear a cluttered terminal without losing your command history. First, produce some output to fill the screen:

ls -la /etc

The long /etc directory listing fills the screen. Now press Ctrl-L.

The screen clears and a fresh prompt appears at the top:

$

The history list is still intact — Ctrl-L only clears the visible display. Confirm this by running:

history | tail -5

You should see output similar to:

   96  ls -la /etc
   97  cat /etc/hostname
   98  ls -la /etc
   99  uname -r
  100  history | tail -5

This matches the final state shown in What We'll Build.

Keyboard Shortcuts Reference

What We Accomplished

In this tutorial, you:

1. Displayed the numbered history list with history
2. Re-executed the previous command using !!
3. Re-executed a specific command by number using !n
4. Re-executed the most recent matching command using !string
5. Found and ran a command interactively using Ctrl-R incremental reverse search
6. Moved the cursor to the start and end of a line using Ctrl-A and Ctrl-E
7. Discarded an in-progress command using Ctrl-U
8. Deleted the previous word using Ctrl-W
9. Cleared the terminal display using Ctrl-L while preserving history