Merge #10773: Shell script cleanups

Merge #10773: Shell script cleanups

13a81b19d Add quotes to variable assignment (as requested by @TheBlueMatt) (practicalswift)
683b9d280 Fix valid path output (practicalswift)
193c2fb4c Use bash instead of POSIX sh. POSIX sh does not support arrays. (practicalswift)
80f5f28d3 Fix incorrect quoting of quotes (the previous quotes had no effect beyond unquoting) (practicalswift)
564a172df Add required space to [[ -n "$1" ]] (previously [[ -n"$1" ]]) (practicalswift)
1e44ae0e1 Add error handling: exit if cd fails (practicalswift)
b9e79ab41 Remove "\n" from echo argument. echo does not support escape sequences. (practicalswift)
f6b3382fa Remove unused variables (practicalswift)

Pull request description:

  Shell script cleanups:
  * Add required space to `[ -n ]`.
  * Avoid quote within quote.
  * Exit if `cd` fails.
  * Remove `\n` which is not handled by `echo`.
  * ~~Remove redundant `$` in arithmetic variable expression.~~
  * ~~Use `$(command)` instead of legacy form `` `command` ``.~~
  * Arrays are not supported in POSIX `sh`. Use `bash` when arrays are used.
  * ~~`[ foo -a bar ]` is not well defined, use `[ foo ] && [ bar ]` instead.~~
  * ~~`[ foo -o bar ]` is not well defined, use `[ foo ] || [ bar ]` instead.~~

Tree-SHA512: 80f6ded58bce625b15b4da30d69d2714c633e184e62b21ed67d2c58e2ebaa08b4147593324012694d02bf4f1f252844cdff2fd1cf5e817ddb07e2777db7a6390