Not too experienced with Bash. But I do know that you have to quote your variables!

Also it's useful to use SpellCheck.

Notes

• The proper she-bang for Bash is #!/usr/bin/env bash.

Links

• ​Parameter expansion​

• ​Defensive BASH Programming​

• ​Safe ways to do things in Bash (HN comments)

• ​Pure Bash Bible - Collection of pure bash alternatives to external processes.

• ​Bash Infinity - Modern boilerplate / framework / standard library for Bash.