How can I check if a directory exists in a Bash shell script?

Question

What command can be used to check if a directory exists or not, within a Bash shell script?

Answer 1

As per Jonathan's comment:

If you want to create the directory and it does not exist yet, then the simplest technique is to use mkdir -p which creates the directory — and any missing directories up the path — and does not fail if the directory already exists, so you can do it all at once with:

mkdir -p /some/directory/you/want/to/exist || exit 1