Shell prompt: \W shown as '\w', left puzzled

Question

TL;DR:

PS1 is not as it's supposed to be. PS1="\W" shows as \w█ the block being the blinking cursor. The folder name will appear only after directory change. OS is Debian 9.9 Stretch. I'm not quite sure where I've made a mistake and kindly ask for others to take a look and give their educated opinions.

Below is my .bashrc:

RED='\[\033[31m\]'
BOLD_RED='\[\033[1;31m\]'
YELLOW='\[\033[33m\]'
GREEN='\[\033[32m\]'
BLUE='\[\033[01;34m\]'
BOLD_BLUISH='\[\033[01;32m\]'
NORMAL='\[\033[00m\]'

USR='\u'
TIME='\t'
PWD='\w'
DIR='\W'
RIGHTS='\$'
RESET='\[$(tput sgr0)\]'

if [ $(id -u) -eq 0 ]; then
    PS1="$NORMAL\t·$BOLD_RED\u@\h$NORMAL·$GREEN$DIR·$NORMAL\$ $RESET"
else
    PS1="$GREEN\t$NORMAL·$BOLD_BLUISH\u@\h$NORMAL·$BLUE$DIR$NORMAL·\$ $RESET"
fi

Answer 1

It's because PWD is a shell variable. From man 1 bash:

PWD The current working directory as set by the cd command.

Bash updates this variable whenever the current working directory changes. It appears that if PS1 uses \W or \w, the prompt reads from the variable, so if you do (or just did) PWD='\w' then the prompt will show literal \w. Try it with another value (e.g. PWD="Oh boy, this string should not appear in my prompt!") and your prompt will reflect this.

After cd the shell updates the variable and the prompt behaves like PS1="\W" should.

General solution: use lowercase names for your variables.