Linux Terminal "sudo apt update" not working
 

I am new to Linux and finally started to try the Terminal (debian) on my Chromebook. The "sudo apt update" that worked when I installed it the first day but now gives me a message:
E: Type ''deb' is not known on line 1 in source list /etc/apt/sources.list.d/signal-xenial.list
E: The list of sources could not be read.

Even if I just start with a fresh launch of Terminal after a hard reset it gives me this message and I am a bit stumped as to what to do next.

Any suggestions?
Randall

 

The issue is as per the the error messages: one of the Apt source list files is incorrect, preventing it from being read, and thus preventing Apt from updating.

You can either try fixing that file yourself (searching for the error message will return plenty of results), or post the contents inside "[code]..[/code]" tags and someone can advise.

Also, in general you should be providing more information - just saying "debian" is not enough - there are multiple supported versions of Debian, and the precise version can be applicable. (If unsure as to what information is relevant, the output of "inxi -b" is often a good start.)