Bash Script Language Fundamentals: Learn How to Automate Tasks

Shell script languages are commonly used in scripts to automate tasks and manage systems. It simplifies these tasks by providing a way to execute commands in sequence and control flow through programming constructs.  

A Bash script is a set of commands written in the Bash shell language. It helps automate tasks and perform operations on a Linux-like system. Here are the commands you need.

Table of contents

1. Bash Script Language Fundamentals
2. Shebang
3. Variables
4. Input/Output
5. Conditionals
6. Loops
7. Functions
8. Command-line arguments
9. File handling
10. Pipes and Redirection:
11. Math operations

Bash Script Language Fundamentals

Shebang

The first line of your Bash script should start with a shebang (#!). This line specifies the path to the Bash interpreter on your system. For example:

!/bin/bash

Variables

You can declare variables to store data. Use the format variable_name=value to assign values.

makefile
name="John"
age=30

Input/Output

Use echo to print output and read to take user input.

echo "Hello, world!"
read -p "Enter your name: " name

Conditionals

if, else, and elif allow you to make decisions based on conditions.

if [ $age -ge 18 ]; then
echo "You are an adult."
else
echo "You are a minor."
fi

Loops

for, while, and until enable you to repeat tasks.

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

counter=0
while [ $counter -lt 5 ]; do
echo $counter
((counter++))
done

Functions

Define reusable code blocks using functions.

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

Command-line arguments

Utilize special variables such as $1, $2, and so on to access command-line arguments

echo "The first argument is: $1"

File handling

Commands like cat, touch, rm, mv, and cp are used for file manipulation.
cat filename
touch newfile
rm oldfile
mv file1 file2
cp file1 file3

Pipes and Redirection:

| (Pipe) connects the output of one command to the input of another, and > or < redirects input/output to/from files.

ls -l | grep "txt" echo "Hello" > greetings.txt 

Math operations

Bash can handle arithmetic operations using (( )).

a=5
b=3
c=$((a + b))
echo "The sum of $a and $b is $c."

Bash scripting commands help automate tasks on Unix-like systems. Test the scripts before using them on the crucial data or systems.

References

• Bash Script Language Fundamentals