M3U files look simple. They're plain text: a header, then pairs of lines where one describes a stream and the next one points to it. Because they're so easy to edit by hand, they're also easy to break. One missing URL line shifts every entry below it, a duplicated link hides in line 4,000, and a typo like htps:// fails silently in most players.

In this post we'll build m3u_check.py , a small command-line linter that:

validates the basic M3U structure

reports entries with no URL (and URLs with no entry)

flags duplicate URLs and duplicate names

warns when tvg-id is missing, so you know EPG data won't match

optionally checks every URL with a concurrent HEAD request

returns a non-zero exit code so you can drop it into CI

No pip install needed.…