SC2163 – ShellCheck Wiki

This does not export `FOO`. Remove `$`/`${}` for that, or use `${var?}` to quiet.

Problematic code:

MYVAR=foo
export $MYVAR

Correct code:

MYVAR=foo
export MYVAR

Rationale:

export takes a variable name, but shellcheck has noticed that you give it an expanded variable instead. The problematic code does not export MYVAR but a variable called foo if any.

Exceptions:

If this is intentional and you do want to export foo instead of MYVAR, you can either use a directive:

# shellcheck disable=SC2163
export "$MYVAR"

Or after (but not including) version 0.4.7, take advantage of the fact that ShellCheck only warns when no parameter expansion modifiers are applied:

export "${MYVAR}"    # ShellCheck warns
export "${MYVAR?}"   # No warning

${MYVAR?} fails when MYVAR is unset, which is fine since export would have failed too. The main side effect is an improved runtime error message in that case.