-d
checks if specified directory exists
-e
checks if specified file exists
-f
checks a file exists and if it is a regular file
-G
checks if a file exists and owned by a specific group
-h or -L
checks if file exists and if its a symbolic link
-O
checks if the file exists and if its owed by a specific UID
-r
checks if file exists and if the read permissoin is granted
-w
checks if file exists and if write permission is granted
-x
checks if the file exists and if execute permission is granted