Linux terminal hacks

Here are some useful terminal hacks.

Aliases

Have a lengthy command and want to make shorter? Use aliases. You can add aliases to your .bashrc file so that they remain permanent.

Consider the following command sudo apt-get install [package name] . You can reduce the number of instructions by adding an alias to the .bashrc file:

The .bashrc file is a shell script file, generally used as a user specific configuration file for the BASH (Bourne Again SHell) shell. It is located in a user’s home directory and will be executed when that user logs into bash. Use  ls -a flag to list all files including hidden files starting with a full stop.

.bashrc file
.bashrc file

After saving the .bashrc file and restarting the terminal you can now run  install zip instead of  sudo apt-get install zip .

The syntax is always  shortname='long command' without spaces either side of the = sign.

PS1 (Prompt String 1)

You can customise the prompt to make it more meaning full.

Historically the original Bourne shell would use a $ as the normal user prompt and # for the root user prompt. This made it easy to tell if you were running as a superuser. The # is also a the comment character, so anyone blindly entering data wouldn’t run any real commands.

A few examples.

  • Check the current PS1 prompt:  echo $PS1
  • Remove the computer name from the prompt:  PS1='\u: \w\$'
  • Add  system inbuilt variables: PS1='$SECONDS [[email protected] W]$ '
  • Add a command output in the prompt: PS1='$(uptime) [[email protected] W]$ '

Tab completion

Just tap tab whenever you want to autocomplete. For example if you’re writing the command  cd med then press tab you will get  cd media/ and if you tap tab again you get  cd media/cdrom .

Pressing tab twice will list commands. For example, if you type  ls then press tab twice you will get a list of all commands starting with  ls :

Bash History

If you want to view your bash history run the command  history | less or  history | tail -n 15 to get only the last 15 lines of your history.

Commands are written to  /home/username/.bash_history

Fun

Want to watch Star Wars in the terminal?

Run  telnet towel.blinkenlights.nl

To exit press  CTRL + ] followed by  quit .

 

 

 

 

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