Automatically find all returned e-mails from “Undelivered messages”

If you’ve got your mails under a text format in a folder (like the unix Maildir) you can use this command to extract the e-mails with a 550 return error.


cat * | grep --text -Pzoi '([a-z0-9._-]+@[a-z0-9.]+)(?=.*host.*said.*55[0-9])'


The first command in the pipe, cat, send all files content to the next command in the pipe : grep. Grep is removing everything except what is an adress, and only if it is followed by “host * said * 55[0-9] ” where * can be everything and [0-9] is a number between 0 and 9. We also use the –text parameter because some mails could contain binary data.


As grep give you the mail separated by new line, and an sql command takes a list of strings separated by comma, you can copy the list in gedit or notepad++ and use search->replace to change them in the format ‘mail1’, ‘mail2’, … You have to put “(.*)” in the search field, “‘\1’,” in the replace by field, and select “regular expression”. You then place the result in the parenthesis after IN, in SQL command below :


UPDATE contact SET mail='' WHERE mail IN ('', '')


Manual network configuration under ubuntu

This procedure is only with cable, not for wifi

First check that your interface is up with the command “sudo ifconfig” :

If like in this screenshot you do not see an interface named “ethXXX“, you have to start the interface manually.
To found which of eth0, eth1, … your network card is, you can type “dmesg | grep eth

We see here that the card “Intel Pro/1000” takes the “eth0” interface name. But it’s later renamed to “eth1“.
So our interface here is eth1, to bring it up, simply run “sudo ifconfig eth1 up”.

You may not have an IP Adress automatically like in this screenshot. If it’s the case, simply type “sudo dhclient eth1” to get one with DHCP.
If it doesn’t work, try to directly ping an IP address like google’s dns server with the command “ping“. If it works, you probably have a nameserver problem. Simply add the line “nameserver” in /etc/resolv.conf

Remove message “Waiting for network configuration…” on ubuntu

On ubuntu, if your system boots without network in failsafe mode, it will wait a long time for network to be available. In many case, this won’t help much…

Moreover, if you’re trying to do things like kernel compiling and for some reason you can’t see the boot log (including this “Waiting for network configuration” message), you’ll have the impression of being stuck with a bad kernel, but in fact it is just waiting 120 seconds…

Just edit the file sudo vi /etc/init/failsafe.conf and remove all “sleep” instructions. The message will be displayed but it won’t wait any time.

To repair you network problems, you might want to check this post and this post.


HDParm is a tool to manage your drives. The first section show you how to get informations about your drives, the second tells you how to make them sleep when they aren’t used (and so make power economy). If you’ve got a home server like me with the system on a SSD, with only your big files on the hard drives(s), you’ll want to do this.


Get disk informations

You’ve got to use “sudo” to gain super user privilege. Your disk are in the /dev/ folder, named sd* where “*” is a letter. To see the list of disk, one can type use “ls /dev/sd[a-z]“:
debserver % ls /dev/sd[a-z]
/dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde


To display informations about one disk, you can use “sudo hdparm -i”


debserver % sudo hdparm -i /dev/sda

Model=WDC WD20EFRX-68EUZN0, FwRev=80.00A80, SerialNo=WD-WCC4M1067803
Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=3907029168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=no WriteCache=enabled
Drive conforms to: Unspecified: ATA/ATAPI-1,2,3,4,5,6,7

* signifies the current active mode


Make a drive sleep after some time

From the manual (man hdparm on the command line):

-S Set the standby (spindown) timeout for the drive. This value is used by the drive to determine how long to wait (with no disk activity) before turning off the spindle motor to save power. Under such circumstances, the drive may take as long as 30 seconds to respond to a subsequent disk access, though most drives are much quicker. The encoding of the timeout value is somewhat peculiar. A value of zero means "timeouts are disabled": the device will not automatically enter standby mode. Values from 1 to 240 specify multiples of 5 seconds, yielding timeouts from 5 seconds to 20 minutes. Values from 241 to 251 specify from 1 to 11 units of 30 minutes, yielding timeouts from 30 minutes to 5.5 hours. A value of 252 signifies a timeout of 21 minutes. A value of 253 sets a vendor-defined timeout period between 8 and 12 hours, and the value 254 is reserved. 255 is interpreted as 21 minutes plus 15 seconds. Note that some older drives may have very different interpretations of these values.


So “sudo hdparm -I /dev/sdb | grep level” will show the current spindown value, for Example:

debserver % sudo hdparm -I /dev/sdb | grep level
Advanced power management level: 254


sudo hdparm -S 25 /dev/sdb = spindown after 25*5 seconds.

sudo hdparm -S 245 /dev/sdb = spindown after (245-240)*30 minutes.


If you want to check the state to see if it works :

sudo watch -n 1 "hdparm -C /dev/sdb && hdparm -C /dev/sdc && hdparm -C /dev/sdd && hdparm -C /dev/sde"


You can use /etc/hdparm.conf to make it permanent:
/dev/sdb {
spindown_time = 60



Huawei Honor 3 root + gapps + multilang

From chinese to international version (with root, multilang and gapps)

Just a little tuto about how I managed to re-flash the ROM of the Huawei Honor 3 bought in China with an international ROM from As you may know, all chinese smartphones may include an English version, but never the Google Play store, Gmail, … And of course, are not rooted.

(On windows)

  1. Put your phone in USB debugging mode (see below if you don’t know how)
  2. Go to (disable adblock if you have it)
  3. Download the first file, not the updates. The others are original, un-rooter version without gapps and so on.
  4. Run the .cmd file. (Without the chinese characters it’s called 3__HN3-U01_.cmd). It’s in chinese, but you just have to type “enter”.
  5. After 2 or 3 minutes it will reboot in recovery mode.
  6. Choose “Wipe data/factory reset”, and choose “yes – delete all data”. This step is very important. If you don’t do that, you’ll mix the two roms… Choose also “wipe cache”.
  7. Choose “reboot now”.

Change language






Go in settings. It’s the icon on the main screen with a gear :


Click on the language menu. It’s the one with an icon of letter”A” :


Click on the first item and choose your preferred language :








Enable USB debugging

Like for the language, go in settings and choose “about phone” :



Type 7 times on the “build number menu”. I know it’s weard but it’s the way to do it !


Now, click on the new menu that appeared “developer options”


And finally, check usb debugging :




  • Error at startup : your phone can tell you twice that a process has stop. It won’t come a third time, so just ignore that. You screen may be black a little too, just lock your phone, unlock in message modes and it won’t happen again.
  • Get rid of the Huawei “home” : you cannot really remove it, but you can install “Apex launcher” or “Nova launcher” which arethe normal google home but slightly enhanced. After installing press the home button, choose the apex or nova launcher and type “always”. For them to work properly, you should install google search from the playstore too.
  • If nothing happen after running the .cmd file, maybe you have a driver problem. Install the software of your phone (HiSuite for the Huawei Honor 3.
  • I woudn’t advise doing system updates. If it’s working, don’t try… If you want to try other roms like the ones of, remember always to do a full wipe ! If the installer don’t reboot you in recovery, whhen the system has rebooted, go in the windows command line (type “cmd” in the windows search prompt), go to the folder where your rom installer is and type “adb reboot recovery” to reboot in recovery. I tried a lot of rom on this website and this was the best at time of writing… The only one removing the chinese apps and dooing everything I said is this one. And the changelog between the 113 and 119 version doesn’t seem that important…

Ugly things : Autologin of console at startup

→ Ugly but okay in a development virtual machine…

Add “– – autologin root” at the end of /etc/init/tty1.conf

It will auto-log you as root for the first console. For the others, do the same with /etc/init/tty[1-5].conf

You can autolog as “student” by replacing root by student. It’s a little safer … but still ugly.

How to debug at boot time

If all you get is a black screen when booting, boot in recovery mode to see a little more information :


When you are in the grub menu, choose the “recovery” version

If there is none or if it’s still black type “e” in the grub menu over the kernel entry you want. Find the line starting by linux, and add “ro single recovery” at the end.
Type F10 to boot.


Grub normally have a “Previous versions” menu to allow you to boot with the ubuntu default kernel…


In fact if you get a black screen when booting, chances is that you’re missing some modules. But you can get more:

  • Add a serial device to your virtualbox, select “file” mode, with e.g. /tmp/vbox-jerry
  • run tail -f /tmp/vbox-jerry on your machine to watch that log file,
  • before booting, press e to edit the config and add at the tail of the command line ” console=ttyS0,57600″
  • this will work only for boot time, when syslogd will start, the log will go to /var/log/syslog
  • You can use the /etc/default/grub file like for the screen size (see slides of info0940) to make it permanent

A network problem during boot may stall you for 120 seconds, with or without a black screen ! So wait a little !

Grignoux Cinema

This post is in French as it concerns only people from my area

Grignoux Cinema Grignoux Cinema

Je suis l’auteur de l’application “Grignoux Cinéma” qui permet de voir les horaires des cinémas grignoux à Liège (Churchill, Parc et Sauvenière) sur les terminaux Android. J’ai déposé le code sur Github, et rend donc open source cette application (licence GPL). N’hésitez pas à contribuer, je manque un peu de temps… J’aimerais rajouter certains fonctions comme la recherche par cinéma, une légende, etc…

Lien github

Lien Google Play Store

VM and Kernel compiling troubleshooting

Start’up Troubleshooting


  • Log in as “student” with the password mentioned in the auditorium and the slides.
  • If your virtual machine does not boot, you can check the boot log with a right-click on the virtual machine entry in VirtualBox.
    The kernel installed on ubuntu server *requires* PAE/NX extension to be enabled in your virtual box. This can be tuned in Settings>System>Processor for your virtual machine.
  • Ubuntu remembers which “network card” you have installed, so that interface IDs (i.e. eth0, eth1…) is consistent when you reboot. This may cause you to lose network connectivity when you copy your .vdi from one machine to another. If that happens (boot stalls on networking setup) reset the content of your /etc/udev/rules.d/*persistent-net.rules file.

Building Kernel Troubleshooting

  • The config file you’ve been given should provide all the options for a i386 build of the reference kernel sources. If you’re prompted with [Y/n/m] questions in “make oldconfig” step, you’re very likely to be trying to compile an amd64 kernel itself, which won’t work on the reference virtual machine. It is mandatory to compile the kernel in i386, see Shell, Linux and Kernel slides for more informations.
  • “CONFIG_DEBUG_SECTION_MISMATCH errors” essentially occurs when you’re including unsafe drivers in your kernel. Unless you’re experiencing this during “make bzImage”, you can safely ignore this.
  • quota exceeded while building may occur on ms8xx, with various error messages. use quota -v -s to check how much more space you can eat on the shared filesystem (/home). kdirstat $HOME can assist you in finding files that take too much room. You have 500Mo allowed, clearly not enough to build the kernel in your home directory. Beware, the compiler suite installed on ms8xx makes use of a “compiler cache”, in the (hidden) $HOME/.ccache directory. You’d more likely want to use some location in /tmp for that purpose. If that’s the case, create a personal sub-folder and export CCACHE_DIR=/tmp/OS$USER/ccache before you start compiling the kernel. Alternatively, you may prefer to restrict the size .ccache can grow. Check out the manpage for details.
  • permission denied during make install might occur. Part of the ‘install’ process is designed by your distribution maintainers for upgrading the distribution itself. This usually happens after vmlinuz and friends have been copied to $INSTALL_PATH, so most of the times, you do not need to bother.

Booting Kernel Troubleshooting

  • “init: failed to create pty…” errors on boot? may occur with your custom-built kernel. It’s annoying, but it’s not just you: it’s a bug not yet fixed in the distributed image. Retrieve the update definitions with sudo aptitude update and then selectively upgrade the buggy package (upstart): sudo aptitude upgrade upstart.
    the screen is completely black with your new kernel ? don’t panic (yet). Chances are that you’re missing some modules. The kernel has started, but cannot access some hardware (including fancy graphic modes). Try out the “recovery mode” for the corresponding kernel, then dig kern.log for an explanation. Use “insert CTRL+ALT+DEL” on your vbox’s “Machine” menu to return to the boot.
  • booting takes ages. Most likely, you’re stuck at network configuration. That may take several minutes when no network card is found (cf. Startup) or when modules for the network card cannot be located.