I recently had a vagrant box which was giving a 500 internal error and when checking the Apache error log I found the following error:
/vagrant/.htaccess: Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration
The problem is that headers module is not loaded in Apache so you need to load it and restart. SSH into your vagrant instance (or open a terminal if you’re having this problem on your local LAMP stack) and enable the module:
Then restart Apache
service apache2 restart
Editing the bashrc file in Elementary OS is an easy task, simply open it in your favorite text editor (Elementary OS comes with nano so you can use that).
sudo nano ~/.bashrc
Make any changes you need to that file and then press ctrl+o to save the file and ctrl+x to exit.
Don’t forget to reload your bashrc!