Bash set -u allow single unbound variable

Question

With bash, you can allow set -e to fail a specific command like:

someCommandThatProbablyFails || true

Is there anything for set -u to allow a specific variable to be unbound?

Specifically I'm doing something like:

if [ -n "${1}" ]; then
    SOMEVAR="${1}"
else
    SOME_STUFF_TO_DETERMINE_SOMEVAR
fi

In this case, it's "${1}" that triggers the unbound variable error if nothing was passed into the script from the command line.

Answer 1

You can use an empty string as the default for an unset variable like this:

${POSSIBLY_UNSET_VARIABLE-}