Clementson's Blog

Screen and the Benefit of a Change of Perspective

Saturday, April 22, 2006

Alan Kay once said that "A new point of view is worth 80 IQ points" and this was reinforced for me recently. Now, I have known about the Unix screen and detachtty utilities for years; however, I've always mentally just equated them as being similar utilities. I knew that screen had more features and was larger than detachtty; however, I hadn't really come up with any use cases for the extra functionality in screen (nor had I really tried to identify those use cases as my "perspective" didn't allow me to consider them). My computer had plenty of memory so I wasn't worried about opening multiple consoles. That made me miss "seeing" the utility of being able to detach processes locally and subsequently re-attach them.

Then, a few days ago I started playing around with the terminal version of Emacs. Since startup is really quick, I've started using it for some things in place of Aquamacs (the implementation of Emacs that I normally use). Now, I find myself using screen all of the time. In one screen window, I fire up a bash shell; in a second window, I run a standard terminal emacs and have it start up an IRC session. If I want to connect to a server, I create another window and SSH to the server (I may run either screen or detachtty on the server so that I can disconnect from that session separately). I switch between windows with a keystroke. When I'm finished working for the day, all I do is detach my screen sessions and quit the terminal. What's also convenient is that my server screen/detachtty sessions are detatched and can be re-attached either from my Mac or any other system that I have access to that can run screen/attachtty. This is useful if I want to check up on a server process when I'm not at my normal development machine. I chatted with Drew about this the other evening and he does this all the time; but, until I changed my "perspective", I was unable to see the real potential of screen.

I've started reading some additional material about screen to see what other features I might be able to utilize (comments/advice from others about how they use screen would be appreciated!). Here's my .screenrc file (most of which I've stolen from .screenrc files that others have posted on the net):

#kill screen's startup message
startup_message off

# define a bigger scrollback, default is 100 lines
defscrollback 1024

# An alternative hardstatus to display a bar at the bottom listing the
# window names and highlighting the current window name in blue. 
hardstatus on
hardstatus alwayslastline
hardstatus string "%{.bW}%-w%{.rW}%n %t%{-}%+w %=%{..G} %H %{..Y} %m/%d %C%a "

# Execute .bash_profile on startup
shell -$SHELL

# Use C-z instead of C-a as this makes more sense for Emacs
escape ^za

# ------------------------------------------------------------------------------
# STARTUP SCREENS
# ------------------------------------------------------------------------------

screen bash
screen -t irc 1 emacs -nw --debug-init -f erc