Quite often when reading macosxhints, I read a hint that involves a terminal command, usually a defaults write hidden preferences trick. The easiest way to enter these commands is to copy them from Safari, and paste them on to the command line in Terminal. The problem is that most of the time I'm using xterm running under X11, and it doesn't support cut and paste with Aqua.
One can get around this problem by entering the following at the shell prompt.
pbpaste | sh
That's it. pbpaste is a shell command that writes the contents of the clipboard to standard output; piping it into the shell causes the shell to execute the command that was on the clipboard. pbcopy works in the other direction -- text sent to the standard input of pbcopy ends up on the clipboard. For example:
echo "Hello Aqua" | pbcopy
puts Hello Aqua on the clipboard.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090126091139753