what Happened - I installed audacity (programme) through command line. Help file was missing. I download zip file. Came to know that this file has to be stored in /usr/share folder. When I tried to extract it there, it was failing. I thought its permission problem so changed permission of /usr/share as following
sudo chmod -R ugo=rwx /usr/share
Within few minits after this system started behaving strangely. Then it collapsed. Nothing was happening. Only black screen was there.
So, I forced shutdown but pushing power button and then restarted the system. It went well till BIOS screen, showed the colored Ubuntu letters and in seconds again went blank.
What I tried?
So to solve this I first looked for answeres on "black screen" after BIOS. Almost all of them suggesting that there must be so problem with graphics card. I was not sure about it, so I tried to see if changes in permission has caused some problem. This question has raise relatively similar issue. But as system was down and there was no screen at all I was not knowing where to put the commands. Additionally it was different in two ways - it speaks about /usr/bin and not /usr/share and in my case sudo was working fine. In this situation, with some research, I tried typing "ctrl+alt+f1" and now I was able to see tty1 type. I am root on this machine and as said earlier sudo was working fine. Now, I tried the combination of suggestions I found in above mentioned question and also here and here and here.
shutdown now or
reboot or even
sudo reboot were not working. PC was not shutting down.
sudo pkexec it came with some message saying I should go to look for help and
disable internal agent and
[username] PROGRAMME [Argument]
repair command, I it came up with permission error 13
sudo apt-get update it also came with permission error 13, access denied.
There was one more message
Sorry, command-not-found has crashed! Please file a bug report at Most of the questions addressing this issue discuss about problem caused by
Now I am unable to "capture" the outcomes of the commands as it is in tty1 mode and the outputs are too long to remember. In this situation what will help me in rebooting to normal mode?
/usr/shareto original. You cant simply give world permission to
/usr/share, it also being use by other system utility.