Basic syntax: What is it really?¶

Bash (or Bourne Again SHell) is a command-line interpreter used on Unix-based systems like GNU/Linux.

A bash script is a text file containing a series of commands that you would normally write in a terminal.

It starts out like this:

#!/bin/bash
echo "Hello, World!"

The #!/bin/bash is called a shebang. It tells the system to use Bash to interpret the script.

Then, you need to make the script executable. You can do this by running chmod +x path/to/script.sh in your terminal.

Variables¶

Declare a variable like this:

name="Vraj"

Use a variable like this:

echo "Hello, $name!"

Read input into a variable like this:

echo "Enter your name:"
read user_name
echo "Hello, $user_name!"

Use the syntax below to perform a conditional check:

if [ $user_name = "Vraj" ]; then
    echo "Welcome back, Vraj!"
else
    echo "Hello, stranger!"
fi

You can also compare numbers using the following operators: -eq, -ne, -lt, -le, -gt, and -ge.

Use the for and while loops to iterate over a range of values.

For example:

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

Or:

count=1
while [ $count -le 5 ]; do
    echo "Count: $count"
    ((count++))
done

Declare a function like this:

greet() {
    echo "Hello from function!"
}

Call a function like this:

greet

Or, you can call a function with arguments:

greet() {
    echo "Hello, $1!"
}
greet "Vraj"