Abstract: There is a problem with version 59 of ide50.

I have found a workaround, which I am sharing widely -- but I'd really like to alert the upstream package maintainers of the bug, so they can fix it with the next update50.

The Problem: CS50 course materials will tell you that the permissions need to be set as follows:

chmod 711 for directories

chmod 644 for images, HTML, CSS, JavaScript

chmod 600 for PHP files.

In general, this is the correct advice.

However, if you have run update50 recently, you should know that there is a bug requiring chmod 640 instead for PHP files. There are also recurring problems with apache50 being unable to write to PHP session files stored under var/lib/php5 because they are (incorrectly) owned by user and group ubuntu.

I've posted about this elsewhere, but the quickest way to fix these permission errors is to change directory to your project's workspace (in the example below, ~/workspace/pset7 ) and execute the following commands:

cd ~/workspace/pset7/
find . -type d | xargs chmod 711
find . -name *.php | xargs chmod 640
sudo find /var/lib/php5 -name sess_* |sudo xargs chown www-data:www-data

My Question: Does anyone know how I can file a bug report for this, so that it will be seen by the right people?

  • 1
    If you are taking the course through edX, there should be a forum there for posting. There's also Slack and/or Reddit. I'm part of the CS50 AP cohort of teachers, so I'll share this issue there tomorrow. Things tend to get addressed quickly on that forum.
    – Peter
    Commented Aug 1, 2016 at 6:23

1 Answer 1


Official answer: the CS50 team is aware of all the issues we've noted and more. Version 60 will be coming out in the next few days, and it should take care of things.

  • 1
    I noticed version 60 is now available through update50. Does installing this update fix the issue with setting up pset7? I'm asking because after updating and following the steps given by the pset instructions, I'm still getting a "Forbidden" message.
    – dLopez
    Commented Aug 5, 2016 at 22:54

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