The FTP ( File Transfer Protocol ) protocol uses port number 21.

Commands :

Access Control Commands

user name      - user login name
pass string    - user password
acct name      - user account name
cwd  path      - change working directory
cdup           - change to parent directory
rein           - logout user
quit           - logout user and close connection

Transfer Parameter Commands
 
type A         - set file representation mode to Ascii or Image (binary)
stru F         - set file structure mode to File, Record or Page
mode S         - set file transfer mode to Stream, Block or Compressed
port n         - set port number to n for data connection
pasv           - set data connection host to passive mode

FTP Service Commands

retr path      - retrieve file
stor path      - store file
rnfr path      - rename file from 
rnto path      - rename file to
abor           - abort service command
dele path      - delete file
rmd  path      - remove directory 
mkd  path      - make directory
pwd            - print working directory
list [path]    - list directory content or show file information
nlst [path]    - list file names in directory
syst           - show type / name of operating system
stat [path]    - show status of connection and transfer parameters
                 or status of service in progress
help [command] - list of avaible commands on server
noop           - ask server to send an ok reply