sometimes we need to check if a file with a date (or another variable part) in the name existis (or what size it is, etc).

Examples:

vfs.file.exists[/var/log/application2000/log%Y%m%d%.log]

vfs.file.exists[/var/log/application2000/log*.log]

vfs.file.exists[/var/log/application2000/log([0-9]|[A-Z]).log]