Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included in the server configuration Action 'configtest' failed.

Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included in the server configuration
Action 'configtest' failed. The Apache error log may have more information....fail!

Ubuntu - Apache2 error

If you are getting this error, it means you have used rewrite engine in your script but rewrite module is disabled right now.

To solve this error, just enable the rewrite module.

If you are using ubuntu - apache2, run this command in terminal

# sudo a2enmod rewrite
# service apache2 restart

Now try again.

If you are getting this error in RHEL/CentOS or in LAMPP, click here.

Enable and Disable Apache modules

Enable and Disable Apache modules in Ubuntu or CentOS

If you want to enable or disable any module in Apache, this post may be helpful for you.

Enable or Disable Apache module in RHEL or CentOS

In CentOS, we can see all Apache modules in the directory /etc/httpd/modules.
These modules are enabled in the file httpd.conf using following code. 
Here is an example of rewrite module.

LoadModule rewrite_module modules/mod_rewrite.so

If you want to disable this module, just comment the line and restart Apache, now it does not load the module.

If you want to enable it again, just uncomment the line and restart apache. 
Using this method we can enable and disable any module of Apache on CentOS.

Enable or Disable Apache module in LAMPP

The process in LAMPP in same as CentOS.

All modules are mentioned in the file /opt/lampp/etc/httpd.conf

If you want to disable any module, just comment the line and restart LAMPP, now it does not load the module.

If you want to enable it again, just uncomment the line and restart LAMPP. 
Using this method we can enable and disable any module of Apache in LAMPP.

Enable or Disable Apache module in Ubuntu

If you want to disable apache module in ubuntu-apache2, run following command

$ sudo a2dismod module_name

If you want to enable apache module in ubuntu-apache2, run following command

$ sudo a2enmod module_name

Suppose you want to disable or enable rewrite module, you should run :

$ sudo a2dismod rewrite
$ sudo a2enmod rewrite

unetbootin error - 7z not found. This is required for either install mode. Install the "p7zip-full" package or your distribution's equivalent.

unetbootin error - 7z not found. This is required for either install mode. Install the "p7zip-full" package or your distribution's equivalent.

If you are trying to make a bootable pen drive using Unetbootin and it gives you above error.
Now because of this error you are not able to make bootable pen drive, here is the solution for you.

If you are using debian or ubuntu
Install from command line

# sudo apt-get install p7zip

OR
If you are still getting the problem
Go to this link and download the p7zip according to your configuration.

Here you can download the deb file.

Now install it and try to make bootable pen drive again.

You will not get this error.

NOTE : If your machine is 32 bit machine, download i386, if you are using amd 64 bit, download amd64 version.

You can find these links at bottom of the page.

If you are using CentOS or Fedora
Install from command line

# sudo yum -y install p7zip