I probably didn’t select it when I installed Xcode. U can find the individual package on the install disk 1…. go into folder “Xcode Tools” and then “Packages” and double click on X11SDK.pkg.

Well if u…..

1. insert the first install disc
2. scroll down to u see the “Optional Installs” PKG icon & double click on it
3. Follow through options (answering the obvious!) till u get to “Installation Type”
4. Click on “Applications” in the Package window

And u should see this…..

Just check on X11 and install

Now all I do now is “ssh -Y username@server” and I can open an X-window app on the server (on Panther you needed “ssh -X username@server”).

However I prefer to work in iTerm and not the xterm app that came with X11. For this to work you need to set the DISPLAY variable correctly. I groked this from http://xanana.ucsc.edu/xtal/sample.bashrc

# Set the DISPLAY variable -- works for Apple X11 with Fast User Switching

if [[ -z $DISPLAY && -z $SSH_CONNECTION ]]; then
    disp_no=($( ps -awx | grep -F X11.app | awk '{print $NF}' 
                     | grep -e ":[0-9]"  ))
    if [[ -n $disp_no ]];then
        export DISPLAY=${disp_no}.0
    else
        export DISPLAY=:0.0
    fi
    echo "DISPLAY has been set to $DISPLAY"
fi

There r ways of getting X11 up headless from iTerm… but my usage of X11 is just occasional so I’ll leave that to another day.