If I want to check for the existence of a single file, I can test for it using test -e filename or [ -e filename ].
Supposing I have a glob and I want to know whether any files exist whose names match the glob. The glob can match 0 files (in which case I need to do nothing), or it can match 1 or more files (in which case I need to do something). How can I test whether a glob has any matches? (I don’t care how many matches there are, and it would be best if I could do this with one if statement and no loops (simply because I find that most readable).
(test -e glob* fails if the glob matches more than one file.)