I found this very nice article about pack/unpack with ruby.
Today is sysadmin-day: Special thanks to all system administrators: you do a great job!
Most linux-users know $OLDPWD. It's an environment variable to get the recently used directory. Sometimes it would be nice to remember more visited directories. In such cases pushd and popd would be a good choice..
Most common shells do have a directory stack. By looking in the man-page of bash I found the following description of the DIRSTACK:
This article explains how to use sysrq for emergency reboots or shutdowns.
Today I inserted another sim card in my fairphone 2. I want to use LTE with this card, but I wasn't able to configure 4G/3G/2G. 2G was selected and the button was disabled. So I just had 2G. The other card worked as expected and I was able to choose 4G/3G/2G. This bothered me the whole day.
In the evening I figured out how to fix the problem:
Tiva cc3200 is a small board with an integrated wifi-chip. The Linux-kernel needs a few configs to be able to talk to this board using a serial console( via usb):