Basics

Starting the script

Shebang: #! : used by the shell to decide which interpreter to run the rest of the script

  • Starts with a “shebang” #! and path to shell you want script to use #!/bin/bash

Executing the script

  • Assign execution rights to user: chmod u+x <file>.sh
  • chmod –> modifies ownership of a file for the current user: u
  • +x –> execution rights

Variables and data types

  • Every variable is an array so can start using any variable as an array.

Set a variable

thing=1

  • Cannot have spaces in between (NO GOOD: thing = 1)

    • If you want to use a space: (( foo = 3 ))

  • Can also reassign thing=$foo

  • If includes spaces, need to quote around it thing="hello world"

Reference a variable

A reference to a variable is an implicit reference to the first index

echo $thing

  • Use dollar sign $

  • For variable operations and arrays, wrap around braces echo ${foo}

  • Reference index

foo[0]=1
foo[1]=2
echo ${foo[1]} # prints 2

Delete a variable

foo=1
echo $foo
unset foo
echo $foo

References