Screen and Emacsclient: Automatically switching to the Emacs window //at 10:38 //by abe

For a very long time, I use mutt with emacsclient as configured editor and a single GNU Emacs instance started from either .screenrc or .Xsession, depending on the system. And I’m very used to switching the virtual desktop or the screen window after starting a mail in mutt.

Since Debian 5.0 Lenny and Emacs 22, Emacs automatically grabs the focus and switches to the right virtual desktop. So after telling mutt recipient and subject of a new e-mail, it invokes emacsclient and immediately the focus has moved to the running Emacs instance. Because I was used to switch one virtual desktop to the right at that point, I often found my self two desktops to the right until I got used to it. :-)

I usually hate applications which grab the focus without being asked. But in this case I basically asked for it. And there’s no delay like with starting up an application which has to read in some database first – think of Liferea or Rhythmbox which take many seconds to minutes to start up, even on my 2.2 GHz dual core ThinkPad.

In the meantime I got so used to that automatic desktop switch that I forget to switch the screen window in the second scenario where I use this combination: My screen doesn’t automatically switch to the Emacs window (window 1) after I told mutt recepient and subject in window 2.

Knowing that screen is quite scriptable, I found out that only a very small change is needed to my mutt configuration to get that desktop feature to my everyday screen session. I simply replaced the editor setting in my .muttrc with the following line:

set editor="screen -X select 1;emacsclient"

Now mutt tells screen to switch to window 1 (where Emacs is running) and then tells Emacs to open the appropriate file to edit my new mail.

Update Friday, 2009-04-24, 18:22

Even though Zack surely is right with his comment about the multi-terminal feature of the upcoming GNU Emacs 23, I still have Etch (and therefore GNU Emacs 21) on the server where I have my screen session.

So the next step was to switch back to the mutt window (window 2) after I’m finished with editing the mail. Since mutt gives the the file to edit as argument to the contents of $editor, simply adding ;screen -X select 2 at the end of $editor doesn’t suffice.

So I wrote a small shell script (named ~/.mutt/editor.sh) as wrapper which calls all the commands and passes the parameters to the right command:

#!/bin/sh

screen -X select 1
emacsclient -a ~/.mutt/alteditor.sh "$@"
screen -X select 2

Of course, $editor is now set to that script:

set editor="/home/abe/.mutt/editor.sh"

Emacsclient of GNU Emacs 21 already supports the -a option to call another editor in case of not being able to connect to a running Emacs instance. Since I don’t want to switch to another screen window in that case, I wrote a second shell script (named ~/.mutt/alteditor.sh) which switches back to the mutt window and then calls GNU Zile, my preferred low-end emacs clone:

#!/bin/sh

screen -X select 2
zile "$@"
screen -X select 1

I love it!

Useless Statistics, the 2nd //at 19:35 //by abe

Myon recently posted a nice statistic about popular single letter package name prefixes. Just out of curiosity I started wondering about popular single letter package name suffixes:

On a machine with Debian oldstable, stable, testing, unstable and experimental in its sources.list, I ran the following command:

$ apt-cache search -n . | \
    awk '{print $1}' | \
    sed -e 's/.$//' | \
    sort | \
    uniq -c | \
    sort -n

And to my surprise there is a non-obvious winner:

$ apt-cache search -n '^gp.$'
gpa - GNU Privacy Assistant
gpc - The GNU Pascal compiler
gpe - The G Palmtop Environment (GPE) metapackage
gpm - General Purpose Mouse interface
gpp - a general-purpose preprocessor with customizable syntax
gpr - GUI for lpr: print files and configure printer-specific options
gps - Graphical Process Statistics using GTK+
gpt - G-Portugol is a portuguese structured programming language
gpw - Trigraph Password Generator

But since I searched through the binary packages many other hits are more obvious, like the seven packages hbf-cns40-1 to hbf-cns40-7:

      [...]
      4 ar
      4 aspell-f
      4 automake1.
      4 cpp-4.
      4 e
      4 g++-4.
      4 gappletviewer-4.
      4 gcc-4.
      4 gcj-4.
      4 gcompris-sound-e
      4 gfortran-4.
      4 gij-4.
      4 go
      4 gobjc-4.
      4 gobjc++-4.
      4 h
      4 iceweasel-l10n-e
      4 iceweasel-l10n-k
      4 kde-i18n-f
      4 kde-i18n-h
      4 kde-l10n-e
      4 kde-l10n-s
      4 kile-i18n-e
      4 koffice-i18n-e
      4 koffice-i18n-s
      4 koffice-l10n-e
      4 koffice-l10n-f
      4 libqbanking
      4 myspell-f
      4 myspell-h
      4 openoffice.org-help-e
      4 openoffice.org-l10n-b
      4 openoffice.org-l10n-h
      4 openoffice.org-l10n-k
      4 sd
      4 tcl8.
      4 tk8.
      5 aspell-e
      5 aspell-h
      5 iceweasel-l10n-s
      5 kde-i18n-b
      5 kde-i18n-e
      5 kde-i18n-t
      5 kde-l10n-k
      5 openoffice.org-l10n-e
      5 openoffice.org-l10n-t
      5 pa
      5 tc
      6 gc
      6 kde-i18n-s
      6 libdb4.
      6 m
      6 openoffice.org-l10n-n
      6 openoffice.org-l10n-s
      6 s
      7 hbf-cns40-
      9 gp

But there are also some other interesting observations to make:

• OpenOffice.org seems to have by far the biggest number of localisations, with KDE being 2nd.
• There are 6 version of the Berkeley DB in Debian: libdb4.2 to libdb4.7 (including oldstable as mentioned above)

I leave it as an exercise to the reader to find the full names of the other package names starting with s, m, gc, pa or tc and having just one additional character. ;-)