root:could not open file '/etc/apt/sources.list'

[Patrick]

That’s actually just a follow up issue.

command-not-found - WARNING:root:could not open file '/etc/apt/sources.list'

command-not-found works [1], however is showing that warning. WARNING:root:could not open file ‘/etc/apt/sources.list’ Whonix does not ship /etc/apt/sources.list but only files in /etc/apt/sources.list.d/ drop-in folder. ( GitHub - Kicksecure/anon-apt-sources-list: /etc/apt/sources.list.d/debian.list for Security-Focused Linux Distributions ) That is because file /etc/apt/sources.list managed by a package could conflict with local users, causing interactive dpkg config resolution dialog. C…

The real issue probably is that the script you’re executing - without verification of software signatures - runs some program which is not installed.

See also:

Install Additional Software Safely