You can use the asterisk (*) as a wildcard in email addresses when defining
routes and in file names.
Wildcards can appear in the name or domain sections of an email address. The following are valid examples:
*—Valid representation of all email addresses.
*@domain.tld, name@*.tld—Valid representation of the whole name or the domain (not the top level domain (TLD)).
*@*.tld—Valid representation of both the name and the domain (not the TLD).
Wildcards cannot appear in a subdomain or the top-level domain. Wildcards also cannot appear with other letters; they must appear alone. The following are invalid examples:
name@domain.*.tld—Invalid representation of a subdomain.
name@domain.*—Invalid representation of a TLD.
*name@domain.tld—Invalid use in conjunction with a name.
You can use wildcard characters in file names the same way you can use them in email addresses. Use an asterisk in the name or the extension sections of a filename, but not in conjunction with a partial name or extension. The following are valid examples:
*.*—Valid representation of all files.
*.extension—Valid representation of all files of a certain extension.
name.*—Valid representation of files with a specific name but of any extension.
The following are invalid examples:
*name.*—Invalid representation of a name.
name.*extension—Invalid representation of an extension.