Using terminal output as input

[Dotan Cohen <dotancohen@gmail.com>]

I am using a Debian-based distro (Ubuntu). Often I need to use the
output of one terminal command as the input for another. A classic
example is the  which command:
$ which firefox
/usr/bin/firefox
$

Now, I would like to use that output as input, to start firefox. Other
than manually typing it in, is there a way for the user to use the
output directly?

Another example is when the OS lets the user know that she needs to
install a program and gives her the command to install it:
$ ekiga
The program 'ekiga' is currently not installed.  You can install it by typing:
sudo apt-get install ekiga
bash: ekiga: command not found
$

In contrast to the "which" example, the text that the user needs is
buried in the output. Is there a way to use it anyway, without
retyping (and without using the mouse, which I often do not have).
Thanks!

-- 
Dotan Cohen

http://what-is-what.com
http://gibberish.co.il