Behaviour when a glob does not match anything

Preparation

$ mkdir globbing
$ cd globbing
$ mkdir -p folder/{sub,another}folder/content/deepfolder/
touch macy stacy tracy "file with space" folder/{sub,another}folder/content/deepfolder/file .hiddenfile
$ shopt -u nullglob
$ shopt -u failglob
$ shopt -u dotglob
$ shopt -u nocaseglob
$ shopt -u extglob
$ shopt -u globstar

In case the glob does not match anything the result is determined by the options nullglob and failglob. If neither of them are set, Bash will return the glob itself if nothing is matched

$ echo no*match
no*match

If nullglob is activated then nothing (null) is returned:

$ shopt -s nullglob
$ echo no*match

$

If failglob is activated then an error message is returned:

$ shopt -s failglob
$ echo no*match
bash: no match: no*match
$

Notice, that the failglob option supersedes the nullglob option, i.e., if nullglob and failglob are both set, then - in case of no match - an error is returned.