[1] RFC 959 - File Transfer Protocol ( ()) <https://tools.ietf.org/html/rfc959#page-5>
pathname
Pathname is defined to be the character string which must be
input to a file system by a user in order to identify a file.
Pathname normally contains device and/or directory names, and
file name specification. FTP does not yet specify a standard
pathname convention. Each user must follow the file naming
conventions of the file systems involved in the transfer.