List of random tips

They can be distro specific, unspecific, cryptic, easy to read. It doesn't matter. Instead of scribbling your tips on a personal file, dump them here.

• To find more info about the USE flags of package X: emerge gentoolkit && equery uses X
• Find info about any media file :

emerge mplayer
add to ~/.bashrc : 
idmedia(){
        mplayer -identify -frames 0 -ao null -vo null  -vc dummy "$@" 2>/dev/null | grep ID_
}
[~] -> idmedia /media/mp3/Mortal\ love\ -\ All\ the\ beauty\ -\ 07\ -\ I\ want\ to\ die.mp3
ID_AUDIO_ID=0
ID_FILENAME=/media/mp3/Mortal love - All the beauty - 07 - I want to die.mp3
ID_AUDIO_CODEC=mp3
ID_AUDIO_FORMAT=85
ID_AUDIO_BITRATE=192000
ID_AUDIO_RATE=44100
ID_AUDIO_NCH=2
ID_LENGTH=591

• Burn encrypted CDs with dm-crypt :

emerge aespipe cryptsetup (or get the cvs version from http://www.saout.de/tikiwiki/tiki-index.php?page=cryptsetup)
cat some.iso | aespipe -H sha256 -e aes256 > some-encrypted.iso
burn it with cdrecord (or losetup /dev/loop0 some-encrypted.iso)
cryptsetup -c aes -s 256 -h sha256 create cdrom /dev/loop0 
Password: (the password you used with aespipe)
mount /dev/mapper/cdrom /mnt/cdrom 
and voila!
of course you need device-mapper, dm-crypt target in the kernel, aes in cryptography.

• Made a livecd or downloaded one and want to give it a testdrive before you burn it on CD(s)?

USE=softemu emerge qemu
qemu -cdrom /path/to/my.iso -boot d

• Testing your all 1337 new kernel and don't want to actually boot with it so it wouldn't sleep with your girlfriend and kill your cats?

USE=softemu emerge qemu
qemu -kernel /bath/to/bzImage -initrd /path/to/initrd -append "kernel cmdline" -hda /dev/hda -snapshot 

Where :

• kernel is the path to the kernel you want to try
• initrd is the path to the initrd the kernel gonna use (optional)
• append is the cmdline to pass to the kernel (ex : elevator=cfq video=vesafb:mtrr,ywrap,800x600@85 rootflags=nopseudo rootfstype=reiser4 rw) (optional)
• hda/-hdb/-hdc/-hdd are either actual devices so the kernel can use or images
• snapshot so any modifications done to the harddisk(s) wont be saved.

If you are using linkdotnet's 07770777 and wvdial. Add this line to wvdial.conf

Stupid Mode = yes

to add more virtual desktops in xfwm press ALT+INS to remove press ALT+DEL

If for no reason you can't sync your PDA try changing permissions of the serial device

chmod 666 /dev/ttyUSB1