Basic Bash Scripting

Bash is a command language interpreter. It is widely available on various operating systems and is a default command interpreter on most GNU/Linux systems. The name is an acronym for the ‘Bourne-Again SHell’.

Table of Contents

• Comments
• Variables
• Functions
• Conditionals
• Loops
• Execution

Comments

# Single line comment
: '
This is a
multi line
comment
'

Variables

#!/usr/bin/env bash

NAME="John"
echo "Hello $NAME!"

Functions

get_name() {
  echo "John"
}

echo "You are $(get_name)"

Conditionals

if [[ -z "$string" ]]; then
  echo "String is empty"
elif [[ -n "$string" ]]; then
  echo "String is not empty"
fi

Loops

for i in /etc/rc.*; do
  echo $i
done

for ((i = 0 ; i < 100 ; i++)); do
  echo $i
done

for i in {1..5}; do
    echo "Welcome $i"
done

Execution

Make your bash script executable by running this command.

sudo chmod +x script.sh

./script.sh