December 8, 2017 2 min read

Useful Bash commands

Navigating the terminal

Hotkey	Function
⌃ + A	Go to beginning of input
⌃ + E	Go to end of input
⌥ + B	Jump to previous word
⌥ + F	Jump to next word
⌃ + U	Delete to beginning of input
⌃ + K	Delete to end of input
⌥ + D	Delete to end of word
⌥ + W	Delete to beginning of word
⌥ + ⌫	Delete a word

Useful commands:

Command	Function
open .	In macOS, open a Finder window of current directory
open	In macOS, open the specified URL in the default browser window

Variables

Command	Function
$?	Exit status of previous command. 0 for success, nonzero for failure.
$$	Process id of currently running script.
!!	History expansion of contents of previous command.
!n	History expansion of command with number “n”.
!-n	History expansion of command “n” commands behind current one in the history.
!ssh	Execute the last “ssh” command with this.

Reference: http://tldp.org/LDP/abs/html/internalvariables.html

Brace expansion

There’s a ton of useful things you can do with brace expansion. Expand integers:

➜  ~ git:(master) ✗ echo {1..10}
1 2 3 4 5 6 7 8 9 10

Expand characters:

➜  ~ git:(master) ✗ echo {a..z}
a b c d e f g h i j k l m n o p q r s t u v w x y z

Combine expansions:

➜  ~ git:(master) ✗ echo {a..f}{0..5}
a0 a1 a2 a3 a4 a5 b0 b1 b2 b3 b4 b5 c0 c1 c2 c3 c4 c5 d0 d1 d2 d3 d4 d5 e0 e1 e2 e3 e4 e5 f0 f1 f2 f3 f4 f5

Reference: http://wiki.bash-hackers.org/syntax/expansion/brace

Bash history

To navigate history, you can use the up and down arrow keys, or the combinations ⌃p and ⌃n to navigate to previous and next commands, respectively.

Searching Bash history

Use the ⌃r hotkey to trigger a reverse search through your Bash history. Type in a string to query. If it matches, press ↵ to execute it. If not, press ⌃r again to see the next result. To see the previous result, use ⌃s.

Reference: https://www.digitalocean.com/community/tutorials/how-to-use-bash-history-commands-and-expansions-on-a-linux-vps

Configuration

The HISTSIZE variable controls how many commands will be stored in Bash history. It defaults to 10,000, but you can change this in your .bashrc file.

← All posts