Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Chapter 9

1. Why do we need an exit status? So commands can signal to their callers if they succeeded or failed in a simple manner.
2. What is the difference between exit status, exit code and return code? An exit code and return code refer to the same thing. An exit status is a concept, which is brought to life by the exit/return code.

3. Which flag do we use with test to test for:
   • An existing directory -d
   • A writable file -w
   • An existing symbolic link -h (or -L)
4. What is the preferred shorthand syntax for test -d /tmp/? [[ -d /tmp/ ]]. Note that a space after [[ and before ]] is mandatory, or the command will fail!
5. How can we print debug information in a Bash session? Set the -x flag, either in the shell with set -x or when calling a script with ...