hmmm….

I’m aware of many people that use GNU Screen’s copy mode to scroll back through terminal history but don’t actually use copy mode for copying text for later pasting. I was one of those people myself for some time. Screen supports some pretty nifty copy/paste tricks but a few basic key strokes will get you started.

Entering Copy Mode and Scrolling

By default, enter copy mode with CTRL+a then ESCAPE. You can use vi like commands to navigate through the scollback buffer. The arrows and PAGE UP/DOWN should work as well. A few useful commands some may be unfamiliar with:

• M - jumps to the middle visible line
• NN% - jumps to the specified percentage in the buffer (0 - start, 100 - end
• g - jumps to the beginning of the buffer
• G - jumps to the end of the buffer

These keys are even useful when you aren’t using copy mode to copy/paste text.

Copying Text

Once the cursor is at the beginning location, press SPACEBAR to set your first mark. Next navigate to the ending position and hit it again. The second SPACEBAR will set your end mark and exit copy mode. One neat and often useful feature is selecting a rectangle on the screen rather than full lines. Use c and C to set the left and right column margins to the cursor’s current location.

Pasting

Pasting is easy, just hit CTRL+a to activate screen then ] to paste.

There’s More!

There are loads more options such as multiple copy buffers, the ability to append marked text to the buffer rather than replacing it, etc. Check out the man page for more screen goodness.

A new command in screen version 4.00 is the idle command.

idle time command

Executes screen command, command when idle for time seconds. E.g. to rotate through screen windows with a 3 second interval:

idle 3 next

To cancel, idle 0

Caspar Clemens Mierau recently wrote about a nifty Debian package named weather-util and his method for embedding the current temperature into the screen status bar. Quite nifty. I did the same with one small exception, including the predicted probability of precipitation if it exists.

My one liner that runs from cron (split to multiple lines for readability):

 weather -iKACY -f | head -n 9  | \
     awk '/Temperature/ { print $2 "F" }
          /Relative/ { print $3 }
          /precipitation/ { sub (/ chance of.+$/, ""); print "POP " $NF }' | \
     xargs echo > /home/michael/.weather

More details on the full implementation in the original post over at Caspar Clemens Mierau’s blog. And yes, I stole his loadavg stuff too ;)

UPDATE:

Silly me, upon further investigation, two things to note. First, the -i option applies only to current conditions and not to the forecast. In my case I actually want weather -f ACY and /etc/weatherrc takes care of the rest. Secondly, the field number for the precipitation percentage changes, oops. I’ve correctly accounted for this in the updated awk script above.

After making these changes I decided the awk script was getting a bit long for a single line so I went all out creating ~/bin/weather.awk:

#!/usr/bin/awk -f

/Temperature/       { temp = $2 }
/Relative Humidity/ { rh = $3   }
/precipitation/     { sub (/ chance of.+$/, "");
                      precip = $NF;
                      exit
                   }

END{ print temp "F " rh " POP " precip }

My crontab entry now looks like:

*/5 * * * *     weather -f ACY | /home/michael/bin/weather.awk > /home/michael/.weather

Much simpler.