how to put color variables in bash $'...'

Question

I have defined in one file which I source from .bashrc, color constants.. like these..

txtgrn='\e[0;32m' # Green
txtylw='\e[0;33m' # Yellow
txtblu='\e[0;34m' # Blue
txtpur='\e[0;35m' # Purple

When I try to use them in my $PS1 variable I am getting strange results, in that everything looks fine till I press CTRL-R for recursive history search when few characters on the begining scramble, so I am able for example to delete them pressing CTRL-D in shell behind that -> pointer :

I am using $'..' notation, to be able to insert unicode chars..

PS1=$'\xE2\x99\x94 [\\t][\u]->'  

so now, what is the proper way of inserting variable like $txtblu from above, into PS1 line..?

EDIT:

so line like this one:

PS1=$'\n\W\xe2\x98\x85 '$txtpur'\n\n[\t]'$txtrst'[\u]->'

makes rendering of symbols and colors ok, but when I press Ctrl+R, type few chars, and then Ctrl+B few(2 of them I think) characters appear on the beginning of resulting command search which are not belonging to that history line, and I am able to delete them.

Answer 1

First, you need an extra line in your colors file defining the STOP, a way of resetting the colors back to default:

txstop='\e[0m' # reset 

This will be needed to reset the colors after each color change, otherwise everything you type will be colored. Now, the other issue is that bash variables need to be in double quotes or they won't be expanded. Since you're using the $' ' syntax, this will require some quote acrobatics. For example:

PS1=$'\xE2\x99\x94'"$txtblu[\\t]$txstop $txtgrn[\u]$txstop$txtpur->$txstop"  

That looks like this:

Answer 2

When using non-printing characters in PS1, you need to wrap them in \[ and \]. In your example like this:

PS1=$'\n\W\xe2\x98\x85 \['$txtpur'\]\n\n[\t]\['$txtrst'\][\u]->'

Explanation: In order to wrap around long commands correctly, bash computes the length of the prompt. However when the PS1 variable contains non-printing characters, the length is computed wrong. Use \[ and \] to indicate "everything between this has a length of 0".

http://www.tldp.org/HOWTO/Bash-Prompt-HOWTO/nonprintingchars.html