By default in Ubuntu the battery discharge notification was set based on remaining time. The remaining time was never accurate nor even near of prediction which caused sudden shutdown or hibernate while working. The only work around the internet was suggesting was to set the notification for percentage of battery remaining instead of time remaining.
Setting notification for percentage remaining.
Since these settings are in Dconf, we may need dconf-editor to makes this easier. I have explained how to install dconf-editor in Ubuntu : Add applications to system tray blog post.
After installing open the dconf editor and navigate to following path in tree sidebar.
org -> gnome -> settings-demon -> plugins -> power
, or you can try to find “battery” and reach the same.
Then update the following settings,
critical-battery-action : The default action to take when battery is empty. Set the critical-battery-action to hibernate if available.
percentage-action : At what percentage of battery OS should take the default which is set just before. I set it to 5.
percentage-critical : At what percentage of battery you need to get the critical notification. I set it to 10.
percentage-low : At what percentage of battery you need to get the first notification for battery low. I set it to 20.
And finally,
use-time-for-policy : Uncheck the checkbox.
Thats it. you are done. You can either restart the system or logout and login back for the changes to take effect.
In Ubuntu 12.04, we need to whitelist application to show in systray, but Ubuntu 14.04 removed the systray whitelist settings from DConf. This caused issues for applications like xchat, parcellite etc.
System Tray with Xchat
Even though I found lot of solution while googleing, the only one worked for ubuntu 14.04 is,
After installing you need to either logout and login or restart your computer. Now the applications likes xchat can be easily minimized to system tray and open when ever you want.
The mongoDB is setup with upstart, so you can start the service with the following command
sudo service mongodb start
Explore CLI
You can enter into mongoDB CLI to explore more, just type mongo in your terminal
mongoDB CLI
Everything is fine. But when I do unclean shutdown sometimes, mongoDB service won’t start automatically. So after each unclean shutdown I need to do remove the lock file and start service manually.
sudo rm /var/lib/mongodb/mongod.lock
sudo service mongodb start
In Ubuntu, by default system-tray won’t show newly installed apps like Xchat or Zeal. This post will walk you though “How to configure system tray to whitelist any application“.
Dconf Editor
We use dconf-editor to update the system-tray whitelist.
Install
You can easily install it with apt-get.
sudo apt-get install dconf-tools
Run it.
You can either type dconf-editor on terminal or click on dash home and search for dconf-editor.
Dash home search
After opening dconf editor, Navigate to Desktop > Unity > Panel there you can find systray-whitelist.
Systray-whitelist before editing
Double click on the value and update to [‘all’] or add your application name to the list.
You are done. Now just logout and login for changes to take effect. After that When you minimise Xchat or Zeal you can find their icon over system try.
If you are running a ubuntu server on a VM, then I highly recommend you to boot VM as headless. Here I use Oracle VirtualBox as my VM.
Why?
The two advantanges I found are
Saves some amount of RAM.
Anyway I ssh to VM, then one less window opened.
Even before I came to know that I can run VM as headless, I usually boot the VM and keep the window minimized. Then I ssh to VM from my terminal, so I can easily copy and paste text to and fro VM.
For multi-tasking on unix server either we need login into server from multiple terminals. But screen program make this easy and we can open multiple windows from the same login.
Main hi-light of this screen program is even though we lost the connection to server, the screen windows survive and we can resume after the nextlogin. So screen will be useful to run some tedious tasks, so that it will execute in the separate screen and continue the execution even after the ssh connection is timeout.
We can name each screen that we create so that we can easily resume it on next login.
Here are the some useful command for the smooth usage of screen program on server.
screen -S <name>
start new screen
Ctrl + a + c
create new window
Ctrl + d
close the current window
Ctrl + a + d
Detach a window
Ctrl + a + ”
list windows and select
Ctrl + a + n
next window
Ctrl + a + p / Ctrl + a + backspace
previous window
Ctrl + a + S
split horizontally
Ctrl + a |
split vertically
Ctrl + a TAB
switch the screen
Ctrl + a Q
to full screen (remove split)
screen -x
list all screens
screen -r <pid.screenname>
resume screen
This is just a beginning. There are lot more to it.
Have you ever faced this issue while a git clone or a ssh?
Are you struggling to solve the issue? Then you have to read the error message carefully once more. That error message itself gives you the solution to solve it.
You need to remove the old signature from known_hosts file. Be careful that all the verified signatures are stored in the same file, so you need to remove only the one which is related to the changed host. So you can use the command below for achieving this.
Replace the <user> with your logged in username and <example.com> with domain or ip address of the host you need to connect. Make sure that you are trying to connect with the authentic server.
A few months before I wrote an article on how to install phpunit on windows. Now when I tried to install phpunit on ubuntu I faced an error phpunit/PHPUnit requires PEAR Installer (version >= 1.9.4), installed version is 1.9.2 .
Here is the steps which I used to get rid of this error.
Install php-pear sudo apt-get install php-pear
Update its own channel sudo pear channel-update pear.php.net
Upgrade pear sudo pear upgrade-all
Now install PHPunit sudo pear install –alldeps pear.phpunit.de/PHPUnit
Now we can check whether installation is success by typing phpunit in terminal.