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
        

        ---

        How to make your linux installation autologin without gdm or kdm. (xdm doesn't allow this)

        1. First read man inittab
        2. edit /etc/inittab and change this line

        
        1:2345:respawn:/sbin/mingetty tty1
        

        to

        
        1:2345:respawn:/sbin/mingetty --autologin username tty1
        

        3. Well naturally you should now put in ~/.bash_profile the startx command. This would work but if you are logging in through a remote shell (ssh, etc.) the startx command with be issued, which is not what we want. Add the following lines in ~/.bash_profile so it issues the startx command only when logging in takes place from the console.

        
        if ["`tty`" = "/dev/console" -o "`tty`" = "/dev/vc/1"]
        then
        startx
        fi 
        

        1. init q
        2. reboot