A shell script is a computer program designed to be run by the Unix shell, a command-line interpreter.

1. Hello Bash Scripting
2. Redirect to file
3. Comments
4. Conditional Statements
5. Loops
6. Script input
7. Script output
8. how to send output from one script to another script
9. String Processing
10. Numbers and Arithmetic
11. Declare Command
12. Arrays
13. Functions
14. Files and Directories
15. Send Email Via Script
16. Curl in Scripts
17. Professional Menus
18. Wait for filesystem events and inotify
19. Introduction to grep
20. Introduction to awk
21. Introduction to sed file. youtube link
22. Debugging bash scripts

For more information:

• Website: Linuxhint
  
• Youtube: Linuxhint

$#, $@ & $? Bash Built-in variables SHELL SCRIPT LINUX COMMANDS BASH I found the $#, $@ & $? bash built-in variables very useful since I knew linux and today I would like to share their usage. I hope that you don't mind if you already know.

file: test.sh

#! /bin/sh
echo '$#' $#
echo '$@' $@
echo '$?' $?

If you run the above script as

./test.sh 1 2 3

You get output:

$#  3
$@  1 2 3
$?  0

You passed 3 parameters to your script.

1. $# = number of arguments. Answer is 3
2. $@ = what parameters were passed. Answer is 1 2 3
3. $? = was last command successful. Answer is 0 which means 'yes'