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Wednesday, October 22, 2014

Guest Login

Recently there was a need to have a "volatile" guest account on my debian box. The solution it to create a user account with the $HOME in /tmp so it will get wiped out. (This is on Debian Wheezy / stable)

The relevant command is in this answer on SuperUser

> # Create account called guest with $HOME in /tmp
> # and default shell as 'none' so ssh access is not possible
> sudo useradd -mb /tmp -s /bin/false -c "Welcome Guest" guest;
> #Disable the password - Click on "Guest" in login screen
> #Make sure you have users displayed on the login screen!
> sudo passwd -d guest

Now I need to figure out how to display a nice welcome message for the Guest user *after* login (Ubuntu 14.04 does this out of the box)

Sunday, October 19, 2014

Recording Stereo Mix using avconv

Based on instructions here:
http://askubuntu.com/questions/233060/recording-speaker-audio-using-avconv

Identify your device first:

$ pactl list sources | grep output



Get the string under "Name:", it will be something like: alsa_output.pci-[some number].analog-stereo.monitor

Record audio and Video:
avconv -f pulse -i alsa_output.pci-0000_00_1b.0.analog-stereo.monitor -f x11grab -r 30 -s 1920*1080 -i :0.0 -vcodec libx264 -preset ultrafast -ab 320k -t 10 -threads 8 screen.mkv

Record only audio:
 avconv -f pulse -i alsa_output.pci-0000_00_1b.0.analog-stereo.monitor -t 1620 -threads 8 screen.mp3