Category Archives: Linux

Stuff about Linux

Linux: Prevent X11/Xorg from using a (Nvidia) GPU

Hi,

when you install an NVidia GPU to run HPC tasks you usually don’t want that X11/xorg use it. This can be done by force Xorg to use the framebuffer device and prevent the nvidia_drm driver from creating a framebuffer device.
You can check this by nvidia-smi

root@debdev ~ # nvidia-smi 
+---------------------------------------------------------------------------------------+
| Processes:                                                                            |
|  GPU   GI   CI        PID   Type   Process name                            GPU Memory |
|        ID   ID                                                             Usage      |
|=======================================================================================|
|    0   N/A  N/A      1581      G   /usr/lib/xorg/Xorg                          167MiB |
|    0   N/A  N/A      1713      G   /usr/bin/gnome-shell                         16MiB |
+---------------------------------------------------------------------------------------+

Continue reading Linux: Prevent X11/Xorg from using a (Nvidia) GPU

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Linux: Disk recovery with ddrescue

Hi

‘ddrescue –direct’ will open the input with the O_DIRECT option for uncached reads. ‘raw devices’ are not needed on newer kernels. For older kernels see below.
Continue reading Linux: Disk recovery with ddrescue

bash: Redirect all STDIN to a file

Hi,

to simply redirect all incoming input from STDIN to a file you can use less.
Continue reading bash: Redirect all STDIN to a file

Network: Forwarding SNMP Traps by mail with snmptrapd and snmptt

Hi,

this post describes a simply way to forward all traps by E-Mail received via SNMP.

This process is splited in several steps

  • Receive the traps => snmptrapd
  • snmptrapd calls the trapshandler script after each received trap. The trap details are handed over to the script by STDIN
  • The trap handler is /usr/sbin/snmptthandler. This script spools all traps to /var/spool/snmptt
  • The snmptt gets the traps from the spool folder, translate them in a human readable format and calls a custum script defined by snmptt.conf

Continue reading Network: Forwarding SNMP Traps by mail with snmptrapd and snmptt

Linux: Switch keyboard layout in (bash) shell

Hi,

linux allows to change the keybaord layout “on the fly”.
Continue reading Linux: Switch keyboard layout in (bash) shell