Shell scripting is an essential skill for anyone working in a Linux environment. The shell acts as an interface between the user and the kernel, allowing users to execute commands, automate tasks, and manage system functions efficiently. Understanding how to create and run shell scripts can significantly enhance your productivity and streamline your workflow. This article will provide an overview of shell scripting, its importance, and practical examples to get you started.

Examples:

1. Basic Shell Script: A simple shell script to display "Hello, World!" can be written as follows:

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

   To run this script:

   • Save the file as hello.sh.
   • Make it executable: chmod +x hello.sh.
   • Execute the script: ./hello.sh.

2. Variables and User Input: Shell scripts can use variables and accept user input. Here’s an example:

   #!/bin/bash
   echo "Enter your name:"
   read name
   echo "Hello, $name!"

   To run this script:

   • Save the file as greet.sh.
   • Make it executable: chmod +x greet.sh.
   • Execute the script: ./greet.sh.

3. Conditional Statements: Shell scripts can also include conditional logic. Here’s an example using an if statement:

   #!/bin/bash
   echo "Enter a number:"
   read number
   if [ $number -gt 10 ]; then
      echo "The number is greater than 10."
   else
      echo "The number is 10 or less."
   fi

   To run this script:

   • Save the file as check_number.sh.
   • Make it executable: chmod +x check_number.sh.
   • Execute the script: ./check_number.sh.

4. Loops: Loops are useful for repetitive tasks. Here’s an example of a for loop:

   #!/bin/bash
   for i in {1..5}
   do
      echo "Iteration $i"
   done

   To run this script:

   • Save the file as loop.sh.
   • Make it executable: chmod +x loop.sh.
   • Execute the script: ./loop.sh.

5. Functions: Functions help organize and reuse code. Here’s an example:

   #!/bin/bash
   greet() {
      echo "Hello, $1!"
   }
   greet "Alice"
   greet "Bob"

   To run this script:

   • Save the file as functions.sh.
   • Make it executable: chmod +x functions.sh.
   • Execute the script: ./functions.sh.