ultimate .bashrc-prompt

# .bashrc-prompt

## prompt
#PS1="\\u@\\h:\\w\\$ " #factory default
## define colors
BLACK='\e[30m'
RED='\e[31m'
GREEN='\e[32m'
YELLOW='\e[33m'
BLUE='\e[34m'
MAGENTA='\e[35m'
CYAN='\e[36m'
WHITE='\e[37m'
#BRIGHT='\e[01m'
#NORMAL='\e[0m'
#BLINK='\e[05m'
#REVERSE='\e[07m'

# note: must be `function [FUNCNAME]' declaration otherwise Bash will throw an
#   error
#   ... No, I don't know why.

function _cmod() {
    local \
        mod="$1"
    shift 1

    if [ -n "$*" ]; then
        echo "$*" |
        sed -e 's,\\e\[\([0-9]*;\)\?,\\e['"$mod"';,g'
    else
        echo '\e['"$mod"'m'
    fi
}

function BRIGHT() {
    _cmod 01 "$*"
}

function NORMAL() {
    _cmod 0 "$*"
}

function BLINK() {
    _cmod 05 "$*"
}

function REVERSE() {
    _cmod 07 "$*"
}


case "$HOSTNAME" in
    'necronomicon.slackware')
        BASE_COLOR="$RED"
        BASE_COLOR_ROOT="$BLUE"
        ;;
    'shell.sf.net')
        BASE_COLOR="$GREEN"
        BASE_COLOR_ROOT="$YELLOW"
        ;;
    *)
        BASE_COLOR="$MAGENTA"
        BASE_COLOR_ROOT="$CYAN"
        ;;
esac

if [ "$UID" -eq 0 ]; then
    PS1='\['$(BRIGHT "$BLACK")'\]=[\l \['$BASE_COLOR_ROOT'\]\u\['$(NORMAL "$WHITE")'\]@\['$BASE_COLOR_ROOT'\]\h\['$WHITE'\] \w \['$(BRIGHT "$BLACK")'\]]=\['$WHITE'\] \$\['$(NORMAL)'\] '

else
    PS1='\['$(BRIGHT "$BLACK")'\]=[\l \['$BASE_COLOR'\]\u\['$(NORMAL "$WHITE")'\]@\['$BASE_COLOR'\]\h\['$WHITE'\] \w \['$(BRIGHT "$BLACK")'\]]=\['$WHITE'\] \$\['$(NORMAL)'\] '
fi

# prepend error string checking, as any prior command will overwrite $?
#PROMPT_COMMAND="err=\$?; [ \$err -ne 0 ] && echo -e '$NORMAL$YELLOW'\"[\$err]\"${PROMPT_COMMAND:+ ; $PROMPT_COMMAND}"
## (this one ensures $err doesn't escape and uses better quoting)
PROMPT_COMMAND='(err="$?"; [ "$err" -eq 0 ] || echo -e '\'"$(NORMAL "$YELLOW")"\''"[$err]")'"${PROMPT_COMMAND:+ ; $PROMPT_COMMAND}"

# clean up
unset \
    BLACK \
    RED \
    GREEN \
    YELLOW \
    BLUE \
    MAGENTA \
    CYAN \
    WHITE \
    BRIGHT \
    NORMAL \
    BLINK \
    REVERSE \
    _cmod \
    BASE_COLOR \
    BASE_COLOR_ROOT

# April Fools' Day prank
if [ "$(date +%m%d)" == '0401' ]; then
    PROMPT_COMMAND+=' ; (if [ $RANDOM -le 8000 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi)'
fi