Need to report on un-set environment variables

[wardmw]

For bugs with existing features

Not an existing bug that I can find.

Here's a snippet or screenshot that shows the problem:

#!/usr/bin/env bash
${LS}

Here's what shellcheck currently says:

$ shellcheck ./shell-test.sh $

Here's what I wanted or expected to see:

$ shellcheck ./shell-test.sh ${LS} ^-^ SC9999 (warning): LS is undefined and used as a command. Verify that this is the intention. $

[grische]

That's intended behaviour.

Variables with only capital letters are considered to be externally defined. Use normal lowercase variables if you want them to be checked.

[brother]

Maybe activate the optional check for unassigned uppercase vars?

name:    check-unassigned-uppercase
desc:    Warn when uppercase variables are unassigned
example: echo $VAR
fix:     VAR=hello; echo $VAR

brother ~$ shellcheck -o check-unassigned-uppercase test.sh

In test.sh line 2:
${LS}
^---^ SC2154 (warning): LS is referenced but not assigned.

For more information:
  https://www.shellcheck.net/wiki/SC2154 -- LS is referenced but not assigned.