xterm-256color and setaf question

[sabrina]

Hello! I need help to figure out how tput setaf works on xterm-256color!
If TERM=xterm, then tput setaf 1 works and changes foreground color to red, but it only supports 8 colors. If TERM=xterm-256color, then tput setaf 1 fails with error

tput: not enough arguments (3) for capability `setaf'

What need to be done to make tput setaf work on xterm-256color?
Thank you!

[sabrina]

tput bold cup 5 22 setaf 1 smso;print MENU;tput sgr0

This code works, if TERM=xterm, but fails if TERM=xterm-256color.

[fvgit]

I can't give you an explanation as to the why, but I can show you how to make it work if you really need to use xterm-256color.

BTW, xterm-16color, xterm-88color, and tmux-256color exhibit the same behaviour, whereas your example works without any problems if you use xterm-vt220, tmux, or xterm-color for instance.

Anyway, the error message indicates that you're missing an argument to the setaf capability. So you need to provice a third argument. Try this:

tput bold cup 5 22 setaf 1 1 smso;print Merry Christmas;tput sgr0

Note the extra argument in red between 1 and smso. It doesn't seem to matter what I put there, but it keeps tput happy.

[Head_on_a_Stick]

Raw ANSI escape codes also work:

printf '\033[38;5;196mBah Humbug!\033[0m\n'

https://gist.github.com/fnky/4587193...797#256-colors

[sabrina]

Thank you, indeed xterm-256color requires 3 arguments for setaf: tput setaf 1 1 1. Still I would like to know the meaning of those 3 arguments.
Here is my little Christmas ksh script:

#!/bin/ksh

tput clear
tempterm=$TERM
TERM=xterm-256color
num=22
set -A chararray M e r r y ' ' C h r i s t m a s \!
for i in $(jot 16 34 104)
do
    tput bold smso cup 5 $(( num++ )) setaf $i 1 1
    printf "${chararray[num-23]}"
    tput sgr0
done
print
TERM=$tempterm

To see all 256 colors I use:

printf '\e[48;5;%dm ' $(jot 256 0); printf '\e[0m \n'

[fvgit]

Nice script!

The weird thing about those extra setaf arguments is that although they seem to be required, they get ignored:

This works for me:

tput bold cup 5 22 setaf 1 Bah, Humbug;print Merry Christmas;tput sgr0

as does this

tput bold cup 5 22 setaf 1 rm /bsd;print Merry Christmas;tput sgr0

Obviously the rm /bsd throws no "override... Permission denied" dialogue since it gets ignored.

Kids, don't try this at home! Some arguments to the rm(1) command will get through and depending on the target there will be tears.

I may not have looked hard enough, but the setaf thingie seems underdocumented in OpenBSD. Strange.

[sabrina]

Hello!
I've found the answer: setaf if bugged in the version of ncurses OpenBSD using. Setaf behavior is fixed in the latest version of ncurses.
With TERM=xterm, I set this nice looking prompt in my .kshrc

PS1='\[$(tput smso setaf 3)\]\W\[$(tput rmso op)\]:\!:\[$(tput setaf 1)\]\$\[$(tput op)\] '

[jggimi]

Please consider reporting the bug.

[sabrina]

Hello!
I have sent the bug report.

[sabrina]

Hello!
I received answers from mailing list.
Short summary:
OpenBSD uses version of ncurses from 11 years ago, modified with local changes.
OpenBSD's tput is not from ncurses, it validates the number of arguments separately and that doesn't match what's actually needed by ncurses.
Workaround: use anything for the 2nd and 3rd parameters, both the OpenBSD and ncurses tput commands ignore these. e.g. tput setaf 1 1 1.