? [-f file] Determine whether it is a normal file and exist
? [-d file] Determine whether it is a directory and exist
? [-e file] Determine whether a file or directory exists
>? [-r file] Determin
? [-f file] Determine whether it is a normal file and exist
? [-d file] Determine whether it is a directory and exist
? [-e file] Determine whether a file or directory exists
>? [-r file] Determin