On this page we present the essential keyboard shortcuts and concepts for working efficiently on the command line. For a complete guide see the GNU readline documentation.
[Ctrl] + [a] # move cursor to beginning of line (think: the beginning letter of the alphabet is 'a')
[Ctrl] + [e] # move cursor to end of line (think: 'e' stands for 'end')
[Ctrl] + [u] # delete from cursor to beginning of line
[Ctrl] + [k] # delete from cursor to end of line
[Ctrl] + [w] # delete the last word
Up arrow # cycle backward through your history
Down arrow # cycle forward through your history
Exercise: Paste the line below on to the command line and try out the sequences above:
squeue --start --format="%.7i %.7Q %.14q %6P %.15j %.12u %.10a %.20S %.6D %.5C %R" --sort=S --states=PENDING | egrep -v "N/A" | head -20
How do you move the cursor to the middle of the line? You may be able to use [meta] + [f] and [meta] + [b] to advance forward and backward by words, respectively. What is the [meta] key for your system? On Mac is it the [option] key. On Mac with Terminal, try holding down the [option] key and click with the mouse where you want the cursor to go on the command line.
The [tab] key can be used to autocomplete the command. Most everyone is aware of this but not everyone uses it. Train yourself to use tab completion whenever possible.
Use the following command to return to the previous working directory:
$ cd -
Here is a sample session:
$ pwd
/home/aturing/work
$ cd /tigress/aturing/crypto/research
$ pwd
/tigress/aturing/crypto/research
$ cd -
$ pwd
/home/aturing/work
See pushd, popd and dirs for a more general approach for returning to previous locations.
Rerun the most recent <command> in your history with !<command>. Here is an example:
$ python myscripty.py
$ ll
$ date
$ !p
python myscript.py
$
!p finds the first command in your history that begins with the letter 'p' and runs it. One could have also used !python. See the next section for a modern alternative to !<command>.
Hold down [Ctrl] and press [r] to invoke "reverse-i-search." Then type a letter like 'p' and you will get a match for the most recent command in your history that contains 'p'. Keep typing to narrow your search. When you find the desired command, press [Enter] to execute. Or hit one of the side arrow keys to modify the command before running it. Or press [Ctrl]+[r] to advance to the next match. You can cancel by running either [Ctrl]+[g] or [Ctrl]+[c].
Be sure to explore the shortcuts offered by your text editor. Editors like vim and emacs cannot be mastered in only a few hours. Make sure that you are taking advantage of these tools. To test your vim knowledge, run this command: vimtutor. To improve your vim skills see Intermediate vim by T. Comi of Princeton.
Consider having the [Caps Lock] key remapped to the [Ctrl] or [Esc] key. What other remappings can you make to improve productivity?
This command is useful when you enter a long command that has a mistake. Run fc and that command will be loaded in a text editor where you can make corrections. The command is executed upon exiting the editor. Note that you can also intentionally enter a wrong command so that you can use a text editor to make changes to the command and use the search functionality of the editor to advance to the middle of the line.
To set your text editor of choice, set the following in your ~/.bashrc file:
export EDITOR=/usr/bin/vim # or emacs or nano
A programmable keyboard provides extras keys that can be mapped to various custom functions. There are also pseudo-versions that try to enhance standard keyboards via software and provide lots of additional features. For Windows see AutoHotKey and for Mac see Keyboard Maestro.
Level Up Your Command Line by T. Comi of Princeton
Linux Productivity Tools by ORNL
Advanced UNIX & Shell Computing by ORNL