Happy Sysadmin-Day
Today is sysadmin-day: Special thanks to all system administrators: you do a great job!
Using pushd/popd
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:
Linux: emergency reboot or shutdown with magic commands
This article explains how to use sysrq for emergency reboots or shutdowns.
Using ssh-keygen
ssh-keygen is a very handy tool for managing ssh-keys. By far the most common use of ssh-keygen is for generating ssh-keys. But this tool can do a bit more..
Fairphone2 has a problem with 2 sim cards
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:
Installing cronjobs out of scripts
Sometimes it's necessary to install cronjobs out of scripts. It's not a good idea to directly write to /var/spool/cron/crontabs. Various things might happen like permission problems or simply problems with the format. It's better to make this in two steps.
Weather in...
http://wttr.in is a very nice Weather-Site. It's possible do download the result via curl in a colorful format for the command-line:
Tiva cc3200: Get serial port working under Linux
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):
Recording terminal-sessions
Recording any terminal session to a gif is easy. I use ttyrec to record a session and ttygif to convert it to GIF.