I was trying to install postfix on Ubuntu 11.10 for SMTP support... I typed
sudo apt-get install postfix
and then the installation started.
But during installation a configuration screen popped up which requested me to select an option. Now the problem is that there is no link to accept an option in the configuration screen, and as I can't select an option the installation process stalls.
If i exit the terminal and again try to re-install i get a message
could not get lock /var/cache/apt/archives/lock -open(11. resource temporarily unavailable)
This is similar to this question for accepting an agreement in a debconf question.
⇆ TAB , then return ↵ will let you continue.
Try this command in terminal: sudo dpkg-reconfigure postfix
This will bring up the configuration window again [where you left off]. Use the up/down arrow keys on your keyboard to select an option [where more than one option is displayed], and the left/right arrow key to choose [ok] so the next window option follows on etc. till all fields are completed by you
I had the same problem as in the first image. Esc, Tab, F12 button worked for me.