Log Message:
shellcheck: Import version 0.7.1.

ShellCheck is a GPLv3 tool that gives warnings and suggestions for
bash/sh shell scripts.

The goals of ShellCheck are:

* To point out and clarify typical beginner's syntax issues that cause
  a shell to give cryptic error messages.

* To point out and clarify typical intermediate level semantic problems
  that cause a shell to behave strangely and counter-intuitively.

* To point out subtle caveats, corner cases and pitfalls that may cause
  an advanced user's otherwise working script to fail under future
  circumstances.