It may or may not surprise you to know that the bash shell has a very rich array of convenient shortcuts that can make your life, working with the command line, a whole lot easier. This ability to edit the command line using shortcuts is provided by the GNU Readline library. This library is used by many other nix application besides bash, so learning some of these shortcuts will not only allow you to zip around bash commands with absurd ease :), but can also make you more proficient in using a variety of other nix applications that use Readline. I don’t want to get into Readline too deeply so I’ll just mention one more thing. By default Readline uses emacs key bindings, although it can be configured to use the vi editing mode, I however prefer to learn the default behavior of most applications (I find it makes my life easier not having to constantly customize stuff). If you’re familiar with emacs then many of these shortcuts will not be new to you, so these are mostly for the rest of us :).
Command Editing Shortcuts
Ctrl + a – go to the start of the command line Ctrl + e – go to the end of the command line Ctrl + k – delete from cursor to the end of the command line Ctrl + u – delete from cursor to the start of the command line Ctrl + w – delete from cursor to start of word (i.e. delete backwards one word) Ctrl + y – paste word or text that was cut using one of the deletion shortcuts (such as the one above) after the cursor Ctrl + xx – move between start of command line and current cursor position (and back again) Alt + b – move backward one word (or go to start of word the cursor is currently on) Alt + f – move forward one word (or go to end of word the cursor is currently on) Alt + d – delete to end of word starting at cursor (whole word if cursor is at the beginning of word) Alt + c – capitalize to end of word starting at cursor (whole word if cursor is at the beginning of word) Alt + u – make uppercase from cursor to end of word Alt + l – make lowercase from cursor to end of word Alt + t – swap current word with previous Ctrl + f – move forward one character Ctrl + b – move backward one character Ctrl + d – delete character under the cursor Ctrl + h – delete character before the cursor Ctrl + t – swap character under cursor with the previous one
Command Recall Shortcuts
Ctrl + r – search the history backwards Ctrl + g – escape from history searching mode Ctrl + p – previous command in history (i.e. walk back through the command history) Ctrl + n – next command in history (i.e. walk forward through the command history) Alt + . – use the last word of the previous command
Command Control Shortcuts
Ctrl + l – clear the screen Ctrl + s – stops the output to the screen (for long running verbose command) Ctrl + q – allow output to the screen (if previously stopped using command above) Ctrl + c – terminate the command Ctrl + z – suspend/stop the command
Bash Bang (!) Commands
Bash also has some handy features that use the ! (bang) to allow you to do some funky stuff with bash commands.
!! - run last command !blah – run the most recent command that starts with ‘blah’ (e.g. !ls) !blah:p – print out the command that !blah would run (also adds it as the latest command in the command history) !$ – the last word of the previous command (same as Alt + .) !$:p – print out the word that !$ would substitute !* – the previous command except for the last word (e.g. if you type ‘find some_file.txt /‘, then !* would give you ‘find some_file.txt‘) !*:p – print out what !* would substitute
There is one more handy thing you can do. This involves using the ^^ ‘command’. If you type a command and run it, you can re-run the same command but substitute a piece of text for another piece of text using ^^ e.g.:
$ ls -al total 12 drwxrwxrwx+ 3 Administrator None 0 Jul 21 23:38 . drwxrwxrwx+ 3 Administrator None 0 Jul 21 23:34 .. -rwxr-xr-x 1 Administrator None 1150 Jul 21 23:34 .bash_profile -rwxr-xr-x 1 Administrator None 3116 Jul 21 23:34 .bashrc drwxr-xr-x+ 4 Administrator None 0 Jul 21 23:39 .gem -rwxr-xr-x 1 Administrator None 1461 Jul 21 23:34 .inputrc $ ^-al^-lash ls -lash total 12K 0 drwxrwxrwx+ 3 Administrator None 0 Jul 21 23:38 . 0 drwxrwxrwx+ 3 Administrator None 0 Jul 21 23:34 .. 4.0K -rwxr-xr-x 1 Administrator None 1.2K Jul 21 23:34 .bash_profile 4.0K -rwxr-xr-x 1 Administrator None 3.1K Jul 21 23:34 .bashrc 0 drwxr-xr-x+ 4 Administrator None 0 Jul 21 23:39 .gem 4.0K -rwxr-xr-x 1 Administrator None 1.5K Jul 21 23:34 .inputrc
Here, the command was the ^-al^-lash which replaced the –al with –lash in our previous ls command and re-ran the command again.
There is lots, lots more that you can do when it comes to using shortcuts with bash. But, the shortcuts above will get you 90% of the way towards maximum bash productivity. If you think that I have missed out on an essential bash shortcut that you can’t live without (I am sure I have), then please let me know and I’ll update the post. As usual, feel free to subscribe to my feed for more tips and opinions on all things software development.