Using the shell for fun and profit
A few basic shortcuts and commands I have picked up over the years that have helped me become more efficient when working in a *nix shell.
The shortcuts and commands in this post should work with both bash and zsh.
Moving
CTRL-a
Move to the beginning of line.
CTRL-e
Move to the end of line.
Searching
CTRL-r
This will let you search through the history of commands you have entered. The phrase you search for doesn’t have to be in beginning of the command your looking for, so you can search for commands by entering arguments or filenames. If the first match you get is not the command your looking for just hit CTRL-r again and will move to the previous match.
This is very useful if you do a lot of logging in and out of servers by SSH; just hit CTRL-r
, start typing a part of the hostname or username, hit ENTER
and bang - you’re connecting to the server.
Backgrounding
CTRL-z
This will bring the current application running in the shell to the background. To bring back the backgrounded application use the command fg
.
I use this a lot when I am working in vim and need to do a few shell commands, much faster than splitting the window or opening up a new tab.
Repeating
$ !!
Use the !!
command to repeat the last command you ran, just like doing up-arrow + enter
on the keyboard.
I am using this by binding !!\n
to a convenient key combination so I don’t have to move over the arrow keys to repeat the last command. You can easily create key combinations for stuff like this in iTerm2 by opening Preferences > Profiles > Keys and adding a shortcut with action set to ”Send Text” and ”!!\n”.
$ !ssh
This will repeat the most recent command you entered that started with ”ssh”.
If you are using oh-my-zsh this won’t work by default, to enable you have to remove the line that says setopt hist_verify
in ~/.oh-my-zsh/lib/history.zsh
.
Chaining
$ a-long-running-command && command-depending-on-the-first-one
Your can chain commands by putting them on the same line and using either ;
or &&
to separate them. The problem with ;
is that it will run all the commands no matter what happens and the great thing with &&
is that it will stop if one of the commands fail.
This is really useful when you are working with tasks that will take some time to finish and is dependent of each others success. To illustrate:
$ mkdir hello
$ mkdir hello && echo "I created hello"
mkdir: hello: File exists
$
Opening
$ open .
$ open image.jpg
On Mac OS X there is a command called open
, you can use this to open up a directory or a file like it would have happened if you had double clicked on it in the Finder.
Notes
Most of the shortcuts in the shell are made possible by the great GNU Readline Library, this library is used in many other shell applications which makes the shortcuts available in those as well.
There are of course loads of more short cuts and useful commands to learn. Bash has been around for over 20 years so there has been a few people documenting the features. For example Wikipedia is pretty good starting point for the different keyboard short cuts available in bash.
If you are a Vim user you will probably like vi mode for your shell. With this you can use the commands you know from vim to edit the command line.