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

Use the file program. Considering all directories are also files in Linux, issuing the following command would suffice:

file $directory_name

Checking a nonexistent file: file blah

Output: cannot open 'blah' (No such file or directory)

Checking an existing directory: file bluh

Output: bluh: directory