According to ShellCheck's documentation:
When command expansions are unquoted, word splitting and globbing will occur.
This often manifests itself by breaking when filenames contain spaces.
Related: https://www.shellcheck.net/wiki/SC2046
Related: #470
Some variables, that were unquoted intentionally were converted to arrays.
According to ShellCheck's documentation:
Quoting variables prevents word splitting and glob expansion, and prevents
the script from breaking when input contains spaces, line feeds, glob
characters and such.
Related: https://www.shellcheck.net/wiki/SC2086
Related: #470
