grml-screenrc needs changes for screen 5.0

[akorn]

GNU Screen 5.x introduced several incompatible changes: for example, colours have to be specified numerically now, and the %l string escape to get the load average is gone.

I got started on converting the old screenrc and it's now usable for me, but still not quite the same as it used to be. (In particular, the "bell in window X" message is still messed up.)

I'm sharing what I have so others can use it as a starting point, but it's unlikely I'll be able to commit more of my own time to refining it.

Ideally we'd also be able to support screen 4.x and 5.0 concurrently...

# while this works, forking to run `/bin/cut` once every 5s feels expensive and wasteful
backtick 3 5 5  /bin/cut -d' ' -f1-3 /proc/loadavg
caption always "%{+b}%{= 9;0}$USER@%{= 15;0}%H | %{= 11;0}(load: %3` | %{= 9;0}cpu: %1` | %{= 10;0}net: %2`)  %-21=%{= 15;0}%D %Y-%m-%d %0c"
hardstatus alwayslastline "%{= 1;7 }%n%f %t %{= 7;0} | %?%-Lw%?%{= 4;7}%n%f %t%?(%u)%?%{= 7;0}%?%+Lw%? %{= 7;0}"

[mika]

Related, see https://bugs.debian.org/1082656 + https://tracker.debian.org/news/1743013/accepted-screen-501-1-source-into-unstable/ and the upstream announce of screen 5.0.0 at https://www.mail-archive.com/info-gnu@gnu.org/msg03317.html

Regarding the load average removal I found https://www.mail-archive.com/screen-users@gnu.org/msg04670.html + https://savannah.gnu.org/bugs/?66003 -> https://cgit.git.savannah.gnu.org/cgit/screen.git/commit/?id=99a8b26d7ae221dfdc1bbe8f04f5867f7ebc07bc

This is all rather unfortunate and I'm wondering whether we can actually support screen versions before 5 and >=5 concurrently :-/

[akorn]

A wrapper function/alias could decide which screenrc to load depending on the version of screen installed, but I'm not sure it's worth it.

I suppose the grml-testing release will have to ship a screenrc for screen5, while stable stays with screen4 until the 5.0 screen package hits Debian stable. (I realize this is also not ideal.)

[mika]

Yes, but one problem is that our grml-screenrc is known to be used outside of Grml live systems, see e.g. https://michael-prokop.at/blog/2007/12/22/make-console-work-comfortable/ - so it's independent of what Debian release our ISOs are based on. :-/

Maybe we need to get more conservative of what features we enable/use and encourage folks to switch to tmux (related see grml/grml#157)

[akorn]

It's not like the screenrc changes frequently (which would make supporting two branches very resource intensive). To support non-grml systems, you can just publish a screen4rc and a screen5rc.

(If grml-screenrc moves to screen5, the end result is likely going to be the same anyway: people who use screen 4.x will dig the latest version of the grml-screenrc that still worked with screen4 out of git and use that. Might as well just point a hyperlink to that git revision directly.)

[mika]

Good idea about screen4rc vs screen5rc, thanks and agreed :)

[zeha]

@akorn in which way exactly is the bell message broken?

I see the "~" gets appended literally, but it seems this behaviour existed on screen v4 already?

v4:

v5:

[akorn]

With only my changes to screenrc, from April, the bell message was bright green on a black background. Your screenshot looks more familiar.

That said, I don't know what the :21 and :129x39 means (129x39 could be rows x columns, but 21?), or whether it's useful to have in the bell message. Not a big deal, though.