Composer: file_put_contents(./composer.json): failed to open stream: Permission denied

I had this problem to install laravel/lumen.

It can be resolved with the following command:

$ sudo chown -R $USER ~/.composer/

To resolve this, you should open up a terminal window and type this command:

sudo chown -R user ~/.composer (with user being your current user, in your case, kramer65)

After you have ran this command, you should have permission to run your composer global require command.

You may also need to remove the .composer file from the current directory, to do this open up a terminal window and type this command:

sudo rm -rf .composer

For me, in Ubuntu 18.04. I needed to chown inside ~/.config/composer/

E.g.

sudo chown -R $USER ~/.config/composer

Then global commands work.

In my case I don't have issues with ~/.composer.
So being inside Laravel app root folder, I did sudo chown -R $USER composer.lock and it was helpful.

In my case, .composer was owned by root, so I did sudo rm -fr .composer and then my global require worked.

Be warned! You don't wanna use that command if you are not sure what you are doing.