FreeRDP - A Free Remote Desktop Protocol Implementation
See www.freerdp.com for more information

Usage: xfreerdp [file] [options] [/v:<server>[:port]]

Syntax:
    /flag (enables flag)
    /option:<value> (specifies option with value)
    +toggle -toggle (enables or disables toggle, where '/' is a synonym of '+')

    /v:<server>[:port]          Server hostname
    /port:<number>              Server port
    /w:<width>                  Width
    /h:<height>                 Height
    /size:<width>x<height> or <percent>%        Screen size
    /f                          Fullscreen mode
    /bpp:<depth>                Session bpp (color depth)
    /kbd:0x<layout id> or <layout name> Keyboard layout
    /kbd-list                   List keyboard layouts
    /kbd-type:<type id>         Keyboard type
    /kbd-subtype:<subtype id>   Keyboard subtype
    /kbd-fn-key:<function key count>    Keyboard function key count
    /admin                      Admin (or console) session
    /restricted-admin           Restricted admin mode
    /pth:<password hash>        Pass the hash (restricted admin mode)
    /client-hostname:<name>     Client Hostname to send to server
    /multimon                   Use multiple monitors
    /span                       Span screen over multiple monitors
    /workarea                   Use available work area
    /monitors:<0,1,2...>        Select monitors to use
    /monitor-list               List detected monitors
    /t:<title>                  Window title
    +decorations (default:off)  Window decorations
    +smart-sizing (default:off) Scale remote desktop to window size
    /a                          Addin
    /vc                         Static virtual channel
    /dvc                        Dynamic virtual channel
    /u:[<domain>\]<user> or <user>[@<domain>]   Username
    /p:<password>               Password
    /d:<domain>                 Domain
    /g:<gateway>[:port]         Gateway Hostname
    /gu:[<domain>\]<user> or <user>[@<domain>]  Gateway username
    /gp:<password>              Gateway password
    /gd:<domain>                Gateway domain
    /gateway-usage-method:<direct|detect>       Gateway usage method
    /load-balance-info:<info string>    Load balance info
    /app:<executable path> or <||alias> Remote application program
    /app-name:<app name>        Remote application name for user interface
    /app-icon:<icon path>       Remote application icon for user interface
    /app-cmd:<parameters>       Remote application command-line parameters
    /app-file:<file name>       File to open with remote application
    /app-guid:<app guid>        Remote application GUID
    +compression (default:off)  Compression
    /compression-level:<level>  Compression level (0,1,2)
    /shell                      Alternate shell
    /shell-dir                  Shell working directory
    /sound                      Audio output (sound)
    /microphone                 Audio input (microphone)
    /audio-mode                 Audio output mode
    /multimedia                 Redirect multimedia (video)
    /network                    Network connection type
    /drive                      Redirect drive
    +drives (default:off)       Redirect all drives
    +home-drive (default:off)   Redirect home drive
    +clipboard (default:off)    Redirect clipboard
    /serial                     Redirect serial device
    /parallel                   Redirect parallel device
    /smartcard                  Redirect smartcard device
    /printer                    Redirect printer device
    /usb                        Redirect USB device
    +multitouch (default:off)   Redirect multitouch input
    +gestures (default:off)     Consume multitouch input locally
    /echo                       Echo channel
    /disp                       Display control
    +fonts (default:off)        Smooth fonts (ClearType)
    +aero (default:off)         Desktop composition
    +window-drag (default:off)  Full window drag
    +menu-anims (default:off)   Menu animations
    -themes (default:on)        Themes
    -wallpaper (default:on)     Wallpaper
    /gdi:<sw|hw>                GDI rendering
    /gfx                        RDP8 graphics pipeline (experimental)
    +gfx-thin-client (default:off)      RDP8 graphics pipeline thin client mode
    +gfx-small-cache (default:off)      RDP8 graphics pipeline small cache mode
    +gfx-progressive (default:off)      RDP8 graphics pipeline progressive codec
    +gfx-h264 (default:off)     RDP8.1 graphics pipeline H264 codec
    /rfx                        RemoteFX
    /rfx-mode:<image|video>     RemoteFX mode
    /frame-ack:<number>         Frame acknowledgement
    /nsc                        NSCodec
    /jpeg                       JPEG codec
    /jpeg-quality:<percentage>  JPEG quality
    -nego (default:on)          protocol security negotiation
    /sec:<rdp|tls|nla|ext>      force specific protocol security
    -sec-rdp (default:on)       rdp protocol security
    -sec-tls (default:on)       tls protocol security
    -sec-nla (default:on)       nla protocol security
    +sec-ext (default:off)      nla extended protocol security
    /tls-ciphers                List of permitted openssl ciphers - see ciphers(1)
    /tls-ciphers-netmon         Use tls ciphers that netmon can parse
    /cert-name:<name>           certificate name
    /cert-ignore                ignore certificate
    /pcb:<blob>                 Preconnection Blob
    /pcid:<id>                  Preconnection Id
    /spn-class:<service class>  SPN authentication service class
    +credentials-delegation (default:off)       Disable credentials delegation
    /vmconnect:<vmid>           Hyper-V console (use port 2179, disable negotiation)
    -authentication (default:on)        authentication (hack!)
    -encryption (default:on)    encryption (hack!)
    -grab-keyboard (default:on) grab keyboard
    -toggle-fullscreen (default:on)     Alt+Ctrl+Enter toggles fullscreen
    -mouse-motion (default:on)  mouse-motion
    /parent-window:<window id>  Parent window id
    -bitmap-cache (default:on)  bitmap cache
    -offscreen-cache (default:on)       offscreen bitmap cache
    -glyph-cache (default:on)   glyph cache
    /codec-cache:<rfx|nsc|jpeg> bitmap codec cache
    -fast-path (default:on)     fast-path input/output
    /max-fast-path-size:<size>  maximum fast-path update size
    +async-input (default:off)  asynchronous input
    +async-update (default:off) asynchronous update
    +async-transport (default:off)      asynchronous transport (unstable)
    +async-channels (default:off)       asynchronous channels (unstable)
    /wm-class:<class name>      set the WM_CLASS hint for the window instance
    /version                    print version
    /help                       print help
    /play-rfx:<pcap file>       Replay rfx pcap file
    +auth-only (default:off)    Authenticate only.
    +auto-reconnect (default:off)       Automatic reconnection
    /reconnect-cookie:<base64 cookie>   Pass base64 reconnect cookie to the connection
    +print-reconnect-cookie (default:off)       Print base64 reconnect cookie after connecting
    +heartbeat (default:off)    Support heartbeat PDUs
    +multitransport (default:off)       Support multitransport protocol
    /assistance:<password>      Remote assistance password

Examples:
    xfreerdp connection.rdp /p:Pwd123! /f
    xfreerdp /u:CONTOSO\JohnDoe /p:Pwd123! /v:rdp.contoso.com
    xfreerdp /u:JohnDoe /p:Pwd123! /w:1366 /h:768 /v:192.168.1.100:4489
    xfreerdp /u:JohnDoe /p:Pwd123! /vmconnect:C824F53E-95D2-46C6-9A18-23A5BB403532 /v:192.168.1.100

Clipboard Redirection: +clipboard

Drive Redirection: /drive:home,/home/user
Smartcard Redirection: /smartcard:<device>
Printer Redirection: /printer:<device>,<driver>
Serial Port Redirection: /serial:<device>
Parallel Port Redirection: /parallel:<device>
Printer Redirection: /printer:<device>,<driver>

Audio Output Redirection: /sound:sys:alsa
Audio Input Redirection: /microphone:sys:alsa

Multimedia Redirection: /multimedia:sys:alsa
USB Device Redirection: /usb:id,dev:054c:0268

More documentation is coming, in the meantime consult source files