/etc/resolvconf/update.d/libc: Warning: /etc/resolv.conf is not a symbolic link to /run/resolvconf/resolv.conf

To check if a given package is installed in Debian / Ubuntu, type

dpkg -s <package-name>

To get a neater output use dpkg-query which accepts wildcards as well.

dpkg-query -l <package-name>

In Redhat / Fedora / CentOS use the foll...

sudo: /etc/sudoers is mode 0640, should be 0440?

When a similar message appears when you try to run sudo on your machine, the problem is likely with the permissions of /etc/sudoers file.

Try running

pkexec chmod 0440 /etc/sudoers

```...

I've encountered the following error after installing Sublimetext2 from source on my ubuntu machine. The error says

unable to run package setup with list of packages

in a dialog box when sublime text is opened.

The issue is because of missing...

In linux, we often see the use of ./ or ../ before a file name. Here is the explanation for the same

.  Current Directory
.. Parent Directory

./filename  # referring to file name in current directory
../filename # referring to file name in p...

If you have any trouble in accessing internet using your wired connection and while troubleshooting, if your network manager says that "device is not managed", open the terminal and follow the below steps to fix the issue.

sudo vim /etc/Netwo...

In ubuntu, you have a variety of window managers to choose from. Though Ubuntu 12.04 comes with Unity as the default you can switch back to Gnome, or choose other managers like Cinnamon.

If you want to know, which window manager you are running c...

As we have object.class method in Ruby, to check the class of a variable in Javascript, here is the snippet

var ss = "some string";
alert (typeof ss);  #=> string
alert (typeof pp);  #=> undefined

After installing sublime text, we must be able to open text files with it. Right click on a text file and you must see the option "open with sublime text". In case you don't , click Open with other applications and you should see Sublime text opti...

To delete sessions based on a hard coded cut-off date:

DELETE FROM sessions WHERE updated_at < STR_TO_DATE('23.05.2013',GET_FORMAT(DATE,'EUR'));

Replacing cut-off date with period of inactivity

DELETE FROM sessions WHERE updated_at ...

To copy a folder in the remote server to your local machine,

scp -r username@IPaddres:/remote/directory/path /local/folder/

In case you wish to copy in your current local directory

scp -r username@IPaddres:/remote/directory/path/ .