Bash Profile Setting not working for path - PS1

Question

I've written the following bash profile settings file:

BLACK="\[\033[0;30m\]"
DARK_GRAY="\[\033[1;30m\]"
LIGHT_GRAY="\[\033[0;37m\]"
BLUE="\[\033[0;34m\]"
LIGHT_BLUE="\[\033[1;34m\]"
GREEN="\[\033[0;32m\]"
LIGHT_GREEN="\[\033[1;32m\]"
CYAN="\[\033[0;36m\]"
LIGHT_CYAN="\[\033[1;36m\]"
RED="\[\033[0;31m\]"
LIGHT_RED="\[\033[1;31m\]"
PURPLE="\[\033[0;35m\]"
LIGHT_PURPLE="\[\033[1;35m\]"
BROWN="\[\033[0;33m\]"
YELLOW="\[\033[1;33m\]"
WHITE="\[\033[1;37m\]"
DEFAULT_COLOR="\[\033[00m\]"


function prompt_command {
    # How many characters of the $PWD should be kept
    local pwd_length=23
    if [ $(echo -n $PWD | wc -c | tr -d " ") -gt $pwd_length ]
    then 
        newPWD="$(echo -n $PWD | sed -e "s/.*\(.\{$pwd_length\}\)/\1/")"
    else
        newPWD="$(echo -n $PWD)"
    fi
}
PROMPT_COMMAND=prompt_command;

PS1="\`if [ \$? = 0 ];
then
    echo -e '$PURPLE[\t] $LIGHT_CYAN\u$YELLOW@\h$WHITE: $newPWD $GREEN$ $DEFAULT_COLOR';
else
    echo -e '$PURPLE[\t] $LIGHT_CYAN\u$YELLOW@\h$WHITE: $newPWD $RED$ $DEFAULT_COLOR';
fi; \`"
export PS1;

For some reason getting the newPWD is not working. It is present in the enviroment (I can print it with the echo), however it isn't added to the command lines prompt. There an empty string is added always. So a sample output is:

[11:54:09] ber@szak:  $

Any ideas why not?

---

PS. Here it is my solution to this:

BLACK="\[\033[0;30m\]"
DARK_GRAY="\[\033[1;30m\]"
LIGHT_GRAY="\[\033[0;37m\]"
BLUE="\[\033[0;34m\]"
LIGHT_BLUE="\[\033[1;34m\]"
GREEN="\[\033[0;32m\]"
LIGHT_GREEN="\[\033[1;32m\]"
CYAN="\[\033[0;36m\]"
LIGHT_CYAN="\[\033[1;36m\]"
RED="\[\033[0;31m\]"
LIGHT_RED="\[\033[1;31m\]"
PURPLE="\[\033[0;35m\]"
LIGHT_PURPLE="\[\033[1;35m\]"
BROWN="\[\033[0;33m\]"
YELLOW="\[\033[1;33m\]"
WHITE="\[\033[1;37m\]"
DEFAULT_COLOR="\[\033[00m\]"

export MYPATHPS='$(
    echo -n "${PWD/#$HOME/~}" | 
    awk -F "/" '"'"'{
        if (length() > 14) {
            if (NF>4) print  "/"  "/.../" $(NF-1) "/" $NF;
            else if (NF>3) print  "/"  "/.../" $NF;
            else print  "/.../" $NF;
        }
        else print ;
    }'"'"'
)';

PS1="$PURPLE[\t] $LIGHT_CYAN\u$YELLOW@\h \` if [ \$? = 0 ]
    then
        echo -en '$GREEN'
    else
        echo -en '$RED'
    fi;
\` $MYPATHPS $ $DEFAULT_COLOR ";
export PS1;

Answer 1

You need to export newPWD. Just because you can echo it doesn't mean its in the environment. It means its set in the shell and/or the environment. To know if something is in the environment I would use:

env | grep '^newPWD'

I'm not sure but I don't think that using newPWD like this is going to work, as newPWD is not reset every time you change directory like PWD is. So you may end up needing to change your PS1 setting to call the prompt_command function each time.

From your comments looks like my guess about newPWD was right. So what you need to do is change the prompt_command function to echo the prompt that you want. Then change your PS1 setting to

PS1="\`if [ \$? = 0 ];
                then
                    echo -e '$PURPLE[\t] $LIGHT_CYAN\u$YELLOW@\h$WHITE: $(prompt_command) $GREEN $DEFAULT_COLOR';
                else
                    echo -e '$PURPLE[\t] $LIGHT_CYAN\u$YELLOW@\h$WHITE: $(prompt_command) $RED $DEFAULT_COLOR';
              fi; \`"
export PS1;

Note: I also removed the trailing $ from $RED$ and $GREEN$ as I assumed they were typos. Not sure if that was right