Terminals, termcap, infocmp, $TERM and so on

netbsdnoob

Hello everyone,

I am trying to get a better understanding of terminals and how do they work, why sometimes some control chars work in some terminal emulators other times they don't. Why sometimes I can see colors and fancy chars while other times I don't.

Why sometimes setting the TERM variable fixes stuff?

Can somebody provide a brief explanation of all these terms termcap, terminfo, TERM and how do they relate?

Thanks in advance

rvp

netbsdnoob Text-terminal HOWTO

jmcunx

termcap/terminfo is file(s) used to tell programs how to process characters on the multiple terminals that exists line 20+ years ago (wyse, dec vt ...). I think originally used for cursor positioning.

Why sometimes I can see colors and fancy chars while other times I don't.

That has to do with how whatever terminal you are using is processing the data in these files. There are settings that define what to do when a specific item is about to be "printed".

termcap was just 1 text file, terminfo can be looked as a "compiled" data file or set of files. Historically termcap was used by BSD, terminfo IIRC came from AT&T I think in the sysv days.

But recently even the BSDs seemed to have moved to terminfo.

Me, I always preferred termcap, but seems that file is hardly ever used these days.