Wensveen's Blog

March 12, 2013

Batch converting a directory of FLAC files to MP3

Filed under: Uncategorized — Tags: , , , , , — wensveen @ 12:35 am

Just a quick one, because it took me a while to get the command right. Hope it helps someone out there with a similar problem. I’m using Debian unstable with (unofficial) deb-multimedia repositories enabled.

The magic command I use is:

find . -name "*.flac" -print0 | xargs -0 -n 1 basename -s ".flac" | xargs -n 1 -I % ffmpeg -i %.flac -ab 196k %.mp3

The 1st command of course finds the input files. The 2nd turns filename.flac into filename. The last command runs ffmpeg on all flac files to convert it to mp3 files (at 196kbps).

If you’re running a version of ffmpeg that can’t encode mp3 files (because of format / patent restrictions), you’ll have to pipe the output from ffmpeg into lame or some other mp3 encoder.


November 17, 2012

Reboot to Windows from Linux

Filed under: Uncategorized — Tags: , , , — wensveen @ 1:23 am

I, like many others, have a dual-boot system. I run Debian (unstable / sid) as my primary OS, and Windows 7 when I play games. Hopefully Steam coming to Linux means that I won’t have to reboot anymore, but for the moment I do.

Of course, it’s not really hard to reboot your system and then choose the correct option in th GRUB menu, but it does mean you have to stay around to prevent GRUB from booting the default OS, instead of walking to the kitchen to get a cup of coffee / tea  / [insert beverage of choice here]. Well, there’s a solution for that, a command called grub-reboot. For example:

sudo grub-reboot 6

This will set the 7th entry in the list of OSes as the default for one boot (it’s a 0-based index). Then reboot, et voila! You still have to know which entry to boot, of course, but you can just count it once and remember. Right? Well, it’s not always that simple.

The problem is that sometimes a new Linux kernel is installed and the old one is kept, to be able to reboot safely when the new kernel doesn’t work (which has actually never happened to me, but is a possibility when running Debian unstable). In that case, you might need to reboot to a different entry. Besides that, I wanted to have a nice icon to click on, that would set the grub entry and reboot me in one simple step.

I’ve created a simple shell script that reads the correct menu entry from grub.cfg and sets that up for the next boot. After that the script calls gnome-session-quit to request a reboot (you can choose between Cancel, Restart or Power Off):


# Find the menuentry containing Windows
#entry=`grep menuentry /boot/grub/grub.cfg | grep -n Windows | cut -d":" -f 1`
#entry=`grep -E '^menuentry|submenu' /boot/grub/grub.cfg | grep -n Windows | cut -d":" -f 1`
entry=`grep -E '^menuentry' /boot/grub/grub.cfg | grep -n Windows | cut -d":" -f 1`

/usr/sbin/grub-reboot $(($entry - 1))
# Use line below for gnome
#gnome-session-quit --power-off

# Use line below for xfce
xfce4-session-logout --fast

Update (16-5-2013): The version of Grub I currently use, adds support for submenus. Only top-level menuitems and submenus should be counted.

Update (12-2-2014): The current version of Grub does not count submenu items as bootable items. Changed reboot command to match XFCE, which is my current DE (a script could/should be made to auto-detect this).

Save it as ~/bin/reboot-to-windows.sh (or some such). Use chmod to make it executable. Also, you will probably have to fiddle with write rights to /boot/grub/grubenv. Either create a grub-reboot group that you add all allowed users to, and set that as the group for the file. Or you can add yourself and other allowed users to the ‘root’ group (Beware: This might introduce serious security issues). Or you can just make the file world-writeable (which allows all users to fuck up your system by corrupting the file).

Now, to create an entry in the Gnome-shell menu (yes, I use Gnome-shell), create a file ~/.local/share/applications/RebootWindows.desktop with the following contents:

#!/usr/bin/env xdg-open
[Desktop Entry]
Name=Reboot to Windows

Where ‘your-username’ is your username, obviously. I’m not sure ~/bin/reboot-to-windows.sh will work, instead of a full path. The Icon entry refers to a svg graphic I created, here it is:
Windows reboot desktop icon
Save the file. The entry should now show up and be clickable.


Update (31-12-2012): I forgot a modification in /etc/default/grub:

# Enable grub-reboot

Otherwise, grub will just boot the first entry, no matter what.

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