Writing and executing shell scripts – Linux Shell and Shell Scripting – Linux operating system

To write and execute shell scripts in Linux, follow these steps:

1. Choose a Text Editor:
   • Select a text editor of your choice to write the shell script.
   • Common text editors in Linux include nano, vi/vim, and emacs.
2. Create a New File:
   • Open the text editor and create a new file with a .sh extension (e.g., script.sh).
   • The .sh extension indicates that it is a shell script.
3. Define the Shebang:
   • The shebang is the first line of the script and specifies the interpreter to use.
   • For bash scripts, use #!/bin/bash.
   • For other shells, such as Zsh or Dash, specify the appropriate interpreter.
4. Write the Script:
   • Start writing the shell script in the text editor.
   • Include commands, variables, conditionals, loops, and any other necessary constructs.
   • Add comments using the # symbol to document your script.
5. Save the File:
   • Save the shell script file in a directory of your choice.
   • It’s recommended to save it in a location included in the system’s $PATH variable for easy execution.
6. Set Execute Permissions:
   • Make the shell script file executable by setting the appropriate permissions.
   • Use the chmod command to set the execute permission. For example: chmod +x script.sh
7. Execute the Script:
   • To run the shell script, open a terminal and navigate to the directory where the script is saved.
   • Use the following command to execute the script:./script.sh
8. Providing Command Line Arguments:
   • If your script expects command line arguments, you can pass them after the script name.
   • For example, if your script expects two arguments, use:./script.sh arg1 arg2
9. Viewing Output:
   • The shell script output will be displayed in the terminal.
   • You can also redirect the output to a file using the > or >> operators.
   • For example, to redirect the output to a file named output.txt, use:./script.sh > output.txt

By following these steps, you can write and execute shell scripts in Linux. Shell scripting is a powerful tool for automating tasks and performing system administration operations in a convenient and efficient manner.