Archive for the ‘Linux’ Category

Convinient GRUB multi-boot configuration

Sunday, June 19th, 2011

These two lines in /etc/default/grub let grub2 remember what system you booted last time and will automatically start this system when rebooting:

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

You need to update grub2 afterwards to have the new configuration activated:

update-grub

PDF Printer with Linux

Thursday, October 1st, 2009

I use a PDF Printer on my professional Windows notebook. It enables me to create PDF documents from whatever application. So, how about Linux then. Thanks God, there is cups-pdf. A German tutorial can be found here. If you find a English HowTo, just post the link here.

Switch Off Caps-Lock

Friday, August 21st, 2009

I was always annoyed by CAPS-LOCK key on my Linux notebook. Thanks god, there is a solution:

xmodmap -e "remove lock = Caps_Lock"

will switch this damn thing off. :)

Extending filesystem on RHEL with LVM

Tuesday, January 6th, 2009

You need to extend a filesystem on a RedHat box? Check the filesystems with df -H. You might get something like

Filesystem             Size   Used  Avail Use% Mounted on
/dev/mapper/system-root
11G   8.0G   2.0G  81% /
/dev/cciss/c0d0p1      104M    18M    81M  19% /boot
tmpfs                  2.1G      0   2.1G   0% /dev/shm
/dev/mapper/system-tmp
4.2G   146M   3.9G   4% /tmp
/dev/mapper/system-var
4.2G   873M   3.1G  23% /var
/dev/mapper/system-mysqllv
11G   8.1G   1.8G  83% /var/lib/mysql
/dev/mapper/system-srvlv
47G    16G    29G  35% /srv

You need to increase the volume capacity first, e.g. for /srv mount:

lvextend -L +15G /dev/system/srvlv

where +15G tells the command to extend the volume by another 15GB.

Last step is to adjust the filesystem to that volume’s new size:

resize2fs /dev/mapper/system-srvlv

That’s it :)

Integrating SpamAssassin with qmail: Part 2

Wednesday, December 24th, 2008

This is a series of articles covering integration of SpamAssassin with qmail on a Linux box.

Part 1: Installing and Configuring SpamAssassin
Part 2: Marking email as spam

Part 2: Marking email as spam

Now, that we setup SpamAssassin to run as a continous process, we are able to change the qmail system to feed all emails into the server daemon. We need the root folder of qmail first. This is usually at /var/qmail. However, you better check with your installation first.

Create a file “qmail-queue.spamd” in subfolder bin that contains a single line:

/usr/bin/spamc -U /tmp/spamd_full.sock| /var/qmail/bin/qmail-queue.orig

Adapt the paths if necessary. Next step is to rename the existing qmail-queue program in subfolder bin. Name it “qmail-queue.orig”, as we have already used that pathname in our script. Make sure that all file permissions of qmail-queue.orig and qmail-queue.spamd match exactly the original qmail-queue binary.

Last step is to replace the existing qmail-queue binary by a link to our qmail-queue.spamd script. That’s it. All your emails do now pass the SpamAssassin daemon. You can check this by viewing all headers of emails passing your system. They should now contain additional SpamAssassin lines.

This is not the end of the story. We just marked email so far as spam or not. The will not get filtered out of the boxes, yet. This however is the topic of part 3 of this series.

Integrating SpamAssassin with qmail: Part 1

Sunday, November 23rd, 2008

This is a series of articles covering integration of SpamAssassin with qmail on a Linux box.

Part 1: Installing and Configuring SpamAssassin
Part 2: Marking email as spam

Part 1: Installing and Configuring SpamAssassin

There are quite a few numbers of HOWTOs at the internet about installing the software itself. So I won’t go very much into details but rather point you to some locations where you can find sufficient information.

You’ll find the latest software package at Apache’s SpamAssassin Homepage. Unpack the archive, preferrably at /usr/local/src. It will produce a directory Mail-SpamAssassin-XXXX. Change into that directory and read the INSTALL file to learn about special features when building the spam recognition tool. Usually you need to issue three commands:

perl Makefile.PL
make
make install

That’s it. Be aware that you might need to enhance your Perl distribution by additional modules from CPAN.

The last step to perform is to make a tool called spamd running continously on your box. We will first configure the daemon according to your Linux distribution. On latest SuSE editions this is done by a file /etc/sysconfig/spamd:

## Path:           Network/Mail/Spamassassin
## Description:    Arguments for the spam daemon
## Type:           string
## Default:        "-d -c -L"
## ServiceRestart: spamd
#
# The arguments passed to spamd.
# See spamd(1) man page.
# Default is "-d -c -L"
SPAMD_ARGS="-d -c -u spamd -g spamd --socketpath=/tmp/spamd_full.sock"

We introduced a user and group called “spamd” here. You might need to configure them first on your system.

Finally, you can add according startup commands in your /etc/rc.d directory to make spamd starting at system boot. Here is a script that I use.

Part 2 of this series will concentrate on the issue how to pass each mail into SpamAssassin.

Firefox 3 crash on Linux with Flash

Monday, July 28th, 2008

Since I installed the latest Firefox version on my openSuSE 11 box, it started to crash constantly on some websites, e.g. Jon Stewarts Full Episode player or the German news channel of Tagesschau. A lot of Google research did not reveal anything useful. Some users reported advance when de-installing AdBlock. That didn’t work, though.

At some forum I read that there are conflicts with pulseaudio installation together with flashplayer. So I deinstalled all pulseaudio packages. I had to restart my Gnome Desktop Manager (gdm). But finally it worked out. All flash videos now play perfectly, Jon Stewart as well as Tagesschau.

So you might want to give that a trial.

VMWare with USB devices on Linux

Friday, June 27th, 2008

VMWare Server depends on USBFS information to recognize USB devices and forward its communication to the virtual machine. OpenSuse switched off this feature by default. In order to re-enable it, you just need to make a slight change in your /etc/fstab file:

usbdevfs /proc/bus/usb usbfs auto 0 0

Usually the line already exists with noauto. Just change it as displayed above. This will mount the filesystem automatically at system start. If you don’t wanna reboot, you can mount the filesystem immediately with:

mount usbfs

PS: This will propably work on every Linux distribution. A detailed description on this topic can be found at openSuse’s homepage.

Laptop Touchpad Configuration

Sunday, June 15th, 2008

I am usually annoyed by the tap mechanism of my Lenovo Thinkpad. Luckily, there is a solution to switch that feature off. All you need is described here: http://de.gentoo-wiki.com/Synaptics_Touchpad