Basic Linux Commands

Bash scripting is very useful especially in linux machines. It makes it easier to automate your workflows At the end of this article you will be able to run your very first bash script, create variables and use them, take input from the command line and use as a variable in the bash script, and finally you will be able to run if/else loops.

To know which Bash you're in, which bash

To make a new bash file, nano filename.sh This command takes you inside the file.

Nice to Note: All bash files end with .sh the same way javascript files end with .js and react files, .jsx

in the bash file #! /bin/bash tells the program how to interprete the language we will be writing in.

To create a variable, VARIABLE="variable content"

to call the variable echo "This is an example of a $VARIABLE"

There are a bunch of commands at the bottom of the file page. To exit the file: Ctrl + x

• It will prompt you to save the modified buffer

• Type Y to confirm

• Type Enter to confirm your changes

This command will take you out of the bash file

To run the bash file: bash filename.sh

If everything is right it will print out This is an example of variable name

TO ADD VARIABLES FROM THE COMMAND LINE TO THE BASH SCRIPT In the bash script;

• echo "Variables $1 $2 and $3 will be added from the command line"

• Exit the bash file

• On the command line call the bash script file and add the variables the command i.e `bash filename.sh "one" "two" "three"

  • If everything is right it will print out Variables one two and three will be added from the command line

TO ECHO THE RESULT OF A COMMAND Enter the bash script nano filename.sh ;

• Type echo $(whoami) Nice To Know: The 'whoami' command types out the name of the user
• exit the bash script ctrl + X
• on the command line, call the bash script bash filename.sh
• If everything is right, it will print out the name of your user

TO TAKE IN AN INPUT FROM THE COMMAND LINE AND USE AS A VARIABLE IN A BASH SCRIPT Enter the bash script nano filename Type:

• echo "What do you do for fun?"
• read funthings
• Nice To Know: read means whatever the user types in will be used as the value of that variable.

• echo "$funthings are NOT fun"

  • Exit the bash script
  • run the bash script bash filename.sh
  • If everything is right it will allow you take in and input and run the result using the input as a variable

TO USE IF/ELSE STATEMENTS IN A BASH SCRIPT Enter the bash script;

• echo "what is your name"
• read yourname
• ` if [ $yourname ]; then

   echo "yourname is a nice name"
  

  else

   echo "I didn't like you anyways"
  

  fi`

• Always remember to end your loops with "fi" if not will have an error

That's all for now. You can now go out and duct tape you applications!