The following question is from Pro Bash Scripting 2nd Edition:

Exercises By default, where can a variable assigned in a script be accessed? Select all that apply: 1. In the current script In functions defined in the current script In the script that called the current script In scripts called by the current script . In subshells of the current script 2. I advise against uing single-letter variables names but give a couple of places where they are reasonable. Can you think of any other legitimate uses for them? 3. Given var=192.168.0.123, write a script that uses parameter expansion to extract the second number, 168