Bash Shell: Find Out If a Variable Is Set or Not - nixCraft
Linux commands: echo
Bash Scripting 7: Functions and Course Review - YouTube
echo command in Linux with Examples - GeeksforGeeks
Bash Scripting - Bash Read Password without Echoing back - GeeksforGeeks
Shell Scripting for Beginners – How to Write Bash Scripts in Linux
How to Write a Bash Script: A Simple Bash Scripting Tutorial | DataCamp
More advanced if usage
16 echo command examples in Linux
shell script - bash string comparison failure, "command not found" - Unix & Linux Stack Exchange
How to Create Simple Shell Scripts in Linux
Shell scripts | IntelliJ IDEA Documentation
Bash script: YES/NO prompt example - Linux Tutorials - Learn Linux Configuration
debugging - How to debug bash script? - Ask Ubuntu
Bash Echo Command Explained In Linux - OSTechNix
bash - My shell script for checking leap year is showing error - Stack Overflow
Commands not working on Git Bash - Stack Overflow
How to check if bash variable defined in script - nixCraft
Bash Function & How to Use It {Variables, Arguments, Return}
What the heck is my PATH, and how do I get it to do what I want?
BASH Shell Test If a File Is Writable or Not - nixCraft
How do I Exit a Bash Script?
Bash check if process is running or not on Linux / Unix - nixCraft
