Client sends text requests of the following form: #FISH_COMMAND arguments... equivalent shell commands, which may be multi-line Fish commands are all defined, shell equivalents may vary. Fish commands always have priority: the server is expected to execute a fish command if it understands it. If it does not, however, it can try to execute a shell command. When there is no special server program, Unix shell ignores the fish command as a comment and executes the equivalent shell command(s). Server replies are multi-line, but always end with ### xyz<optional text> line. ### is a prefix to mark this line, xyz is the return code. Return codes are a superset to those used in
FTP. The codes 000 and 001 are special, their meaning depends on presence of server output before the end line. == Session initiation ==