Commands may be abbreviated.  Commands are:

!               features        mls             prompt          site
$               fget            mlsd            proxy           size
account         form            mlst            put             sndbuf
append          ftp             mode            pwd             status
ascii           gate            modtime         quit            struct
bell            get             more            quote           sunique
binary          glob            mput            rate            system
bye             hash            mreget          rcvbuf          tenex
case            help            msend           recv            throttle
cd              idle            newer           reget           trace
cdup            image           nlist           remopts         type
chmod           lcd             nmap            rename          umask
close           less            ntrans          reset           unset
cr              lpage           open            restart         usage
debug           lpwd            page            rhelp           user
delete          ls              passive         rmdir           verbose
dir             macdef          pdir            rstatus         xferbuf
disconnect      mdelete         pls             runique         ?
edit            mdir            pmlsd           send
epsv4           mget            preserve        sendport
exit            mkdir           progress        set