Is it possible to highlight the non-breakable space in zsh / terminal?
This highlighting is IMHO more easily implemented in the terminal emulator than in the shell. And as a benefit you get the highlighting independent from the shell -- so it's even working with less
etc.
Since you are fine with switching the shell, I suppose you are fine with switching to URxVt, too.
In conjunction with the perl extentions urxvt-perls it is possible to make URLs etc. clickable. But we can abuse this feature just to underline the non-breakable spaces.
The configuration is done in ~/.Xdefaults
:
URxvt.perl-ext: default,matcher
URxvt.matcher.button: 2
URxvt.matcher.pattern.0: (\\240)
URxvt.matcher.launcher.0: /bin/true
- line 1 activates the appropriate extension
- line 2 configures the usage of the middle mouse button for clicking on the ,,hyperlink''
- line 3 defines the regex to match, here every non-breakable space;
A0 (hex) = 240 (oct)
- line 4 defines the action, in your case you don't want to open up a browser or any program, so
/bin/true
should be fine
Reload ~/.Xdefaults
by restarting the X server (this might be overkill, but I'm not sure if a xrdb ~/.Xdefaults
is sufficient...) and you get your desired result. With a magnifying glass it is even possible to distinguish between non-breakable spaces an underscores (notice the shift by 1 pixel) ;)
:
The following is kind of a proof of concept for a "backend" solution. Be aware, that this will break a lot of things, namely interactive programs like man
, less
etc. (vim
is complaining but still working). This approach was posted by Atom Smasher on the zsh-users
mailinglist on Sat, 16 May 2009 to colorize STDERR
. I adopted it to your requirements:
# ## highlight_nbs.zsh ##
zmodload zsh/terminfo zsh/system
autoload colors is-at-least
if [[ "${terminfo[colors]}" -ge 8 ]] { colors }
highlight_nbs() {
while sysread line
do
syswrite "${line//$'\xC2\xA0'/${bg[red]} ${terminfo[sgr0]}}"
done
}
precmd() { sleep 0 }
## i'm not sure exactly how far back it's safe to go with this
## 4.3.4 works; 4.2.1 hangs.
is-at-least 4.3.4 && exec > >(highlight_nbs)
The tricky part is exec > >(highlight_nbs)
which processes the complete output of the replacing shell through the highlight_nbs
function. The precmd
definition is necessary to avoid a race condition, otherwise the new prompt is printed before the actual output of the executed command.
Here is a demo: