My phone’s bash.profile

Here is some automation that I put into my bash.profile. It’s all done with aliases, since with regular shell scripts, I would first have to remount /mnt/sdcard without ‘noexec’. Like this, I just need to open a ConnectBot “Local” connection, type the alias, and press enter(*).

(*) For this to work, the ‘post login automation’ entry of the ConnectBot “Local” profile needs to have
bash --rcfile /sdcard/bash.profile
in it.

Here is what I have in there:

alias bb="busybox"
alias top="bb top"
alias df="bb df"

alias ll="ls -l"
alias n="su -c \"netstat -ntupl\""

alias backupdata="su -c \"rsync -rP --delete --numeric-ids --chmod=u+rwX --exclude Music /sdcard/ pat@192.168.0.2:/data/pat/g2sd/\""

alias postflash="echo \"Mounting /system read-write\" && su -c \"mount -o rw,remount /system\" && echo \"Copying modified keyboard layout files...\" && su -c \"cp /sdcard/vision-keypad-wwe.kcm.bin /system/usr/keychars/\" && su -c \"cp /sdcard/vision-keypad-wwe.kl /system/usr/keylayout/\" && echo \"Deleting awful camera click sound...\" && su -c \"rm /system/media/audio/ui/camera_click.ogg\" && sync && echo \"All done. Please reboot now.\""

clear
uptime
echo

The first couple of aliases should be self-explanatory.
backupdata is, as the name suggests, to get my SD card’s content to my home server.
postflash is for after flashing a new ROM (usually a CyanogenMod nightly build). It gets my modified keyboard layout into place, and deletes the terrible sound file that gets played when I take a photo with the phone’s camera.

emerge output ends up as attachment.bin when sent with nail / Heirloom mailx

I really like the command line mailer Heirloom mailx (formerly nail), and now there is even a current version in portage again (still under the name mail-client/nail, but that doesn’t matter), so that’s even better. I use it on all servers, since it’s just convenient – it can handle attached files, UTF-8 etc. without any problems.

But there was one problem that bothered me for months already: It involved my check_updates.sh script, which basically just calls /usr/bin/emerge -upvDN --nospinner world for the host and all virtual servers, and then sends the output to me.

The problem: emerge’s output always ended up as ‘attachment.bin’, attached to the (otherwise empty) mail, although I piped it into mail -s "Updates for $DATE" root where it should come out as the mail body. I knew that Heirloom mailx does that, as soon as it doesn’t “like” one of the characters in the input, but I couldn’t think of a reason why it would do that with emerge’s supposedly plain-ASCII output.

Today I had enough of it, and fired up hexdump to investigate said ‘attachment.bin’, using the following command:
hexdump -e '1/1 "%03d \n"' attachment.bin | sort -u
It outputs the unique decimal values of any byte occurring in ‘attachment.bin’ as a sorted list. I expected to find something above 127 – but the highest occurring value was 122 (“z”). I then checked the top part of the list, and to my surprise, found 008 (backspace) there. After removing those by piping the output through tr -d '\010' (8dec = 10oct, and tr needs octal values), Heirloom mailx no longer put the text into ‘attachment.bin’. It now appears in the mail’s body, where it belongs.

By the way, those backspaces (when interpreted) change
Calculating dependencies ... done!
to
Calculating dependencies... done!
… so removing them is not a big loss. I’d like to know though, why they are there in the first place, even though the output doesn’t go to a TTY.

Creating multi-page PDF files with GIMP and `convert`

Occasionally I have to sign some document (old style, with a pen) and send it electronically. Sometimes those are multi-page documents. Since it is uncommon to send it back as multiple image files after scanning, and multi-page image formats are uncommon as well, I’d like to send them as PDF file. Before I discovered this method, I used to insert the scanned images into OpenOffice Writer, and then create the PDF with it. This works, but it is a bit cumbersome to tell OpenOffice Writer to maximise the images (eliminating page borders, etc.), especially when there are a lot of pages. It just doesn’t feel like a real solution.

So, here we go:

Prerequisites:

  • GIMP (I’m currently at version 2.6.8, but this will probably work with older versions as well)
  • GraphicsMagick (tested with 1.3.8) or ImageMagick (tested with 6.5.8.8)

Procedure:

  1. Get the scanned pages opened as layers of one image in GIMP. If they are available as files already, you can use File / Open as Layers….
  2. Make sure that the layers are ordered in the following way: Page 1 must be the bottom layer, the last page must be the top layer. You can reorder them via the “Layers” dialogue (activate it via the Windows / Dockable Dialogues menu if you don’t see it)
  3. Save As… and choose “MNG animation” or just add “.mng” to the filename. (In case you are wondering, MNG is the animated counterpart to PNG).
    A dialogue window saying “MNG plug-in can only handle layers as animation frames” will come up – choose “Save as Animation” here and press the Export button. In the next dialogue you don’t need to make any changes to the defaults, just press the Save button.
  4. Now, open a console window and simply enter
    convert document.mng document.pdf

That’s it – you now have your PDF file ready for sending!

Update (2010-02-08):
As chithanh pointed out in comment 1, there is another convenient way to accomplish the same. It does not involve GIMP, but instead requires pdftk to concatenate PDF files. Please see comment 2 for details.

Update (2010-03-01):
And yet another way (definitely the most straight-forward one, if you have the pages as single image files already) was pointed out by goffrie in comment 5.