Running X11 - 8. Usage Tips

8.1 Launching X11 apps from Terminal.app

To launch X11 applications from a Terminal.app window, you must set the environment variable "DISPLAY". This variable tells the applications where to find the X11 window server. In the default setup - XDarwin runs on the same machine -, you can set the variable as follows:

For tcsh users:
```
setenv DISPLAY :0.0
```
For bash users:
```
export DISPLAY=":0.0"
```

A nice setup is to have XDarwin.app started when you log in (settable in the Login panel of the System Preferences on Mac OS 10.2, in the Accounts panel, Startup items on Mac OS 10.3):

For tcsh users, add the following to your .cshrc file:
```
if (! $?DISPLAY) then
  setenv DISPLAY :0.0
endif
```
For bash users, add the following to your .bashrc file:
```
[[ -z $DISPLAY ]] && export DISPLAY=":0.0"
```

This sets DISPLAY automatically in every shell. It doesn't override the current value when DISPLAY is already set, though. This way you can still run X11 applications remotely or through ssh with X11 tunneling.

8.2 Launching Aqua apps from an xterm

One way to launch Aqua applications from an xterm (or any other shell, actually) is the open command. Some examples:

open /Applications/TextEdit.app
open SomeDocument.rtf
open -a /Applications/TextEdit.app index.html

The second example opens the document in the application that is associated with it, the third example explicitly gives an application to use.

8.3 Copy and Paste

Copy and Paste generally works between the Aqua and X11 environments. There are still some bugs. Emacs is reported to be picky about the current selection. Copy and paste from Classic to X11 doesn't work.

Anyway, the trick is to use the respective methods of the environment you're in. To transfer text from Aqua to X11, use Cmd-C in Aqua, then bring the destination window to the front and use the "middle mouse button", i.e. Option-click on a single-button mouse (this can be configured under XDarwin's Preferences), to paste. To transfer text from X11 to Aqua, simply select the text with the mouse in X11, then use Cmd-V in Aqua to paste it.

The X11 system actually has several separate clipboards (called "cut buffers" in X11 speak), and some applications have weird views which one should be used. In particular, pasting into GNU Emacs or XEmacs sometimes doesn't work because of this. The program autocutsel can help here; it automatically synchronizes the two main cut buffers. To run it, install the autocutsel Fink package and add the following line to your .xinitrc:

autocutsel &

(Make sure it's before the line that exec's the window manager and never returns! Don't just add it at the end, it won't be executed.) And remember that it is no more necessary for Apple's X11 (see Some notes on using Apple's X11).

If you are using Apple's X11, then you can use Command-C or Edit->Copy, as usual for Mac apps, to copy text to the clipboard, and the middle-mouse button or Command-V to paste from the clipboard to Apple X11.

In any case, if you encounter problems copying or pasting from Aqua to X11 and vice-versa, you may first try to do the pasting part twice (it may happen that the copy does not occur at once), then use intermediate applications, e.g. TextEdit or Terminal.app on the Aqua side, nedit or an xterm on the X11 side. In my experience, there is always a solution.