Display a color-coded IEC 60417-5009 power symbol (⏻) in your Bash Primary Prompt String (PS1) when your host needs a reboot.

power-ps1.sh

#############################################################################################
### Display the IEC 60417-5009 power symbol (⏻) at the end of your Bash Primary
### Prompt String (PS1) when the host needs a reboot. Color changes from green
### to red, depending on how many hours the host has
###
### Ex. craigbender@hpz600:~ ⏻
###
### PS1R - Red ⏻ - Host has needed a reboot for > 24 hours
### PS1Y - Yellow ⏻ - Host has needed a reboot for > 12 hours but < 24 hours
### PS1G - Green ⏻ - Host has needed a reboot < 12 hours
###
### Add this code to the end of $HOME/.bashrc, then `source ~/.bashrc`
###
#############################################################################################

# Default Ubuntu/Debian Primary Prompt String
export PS1_NORM='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
# Color-coded with UTF-8 power symbole
export PS1R='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\e[1;38;2;255;0;0m ⏻  \[\033[00m\]\$ '
export PS1Y='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\e[1;38;2;255;255;0m ⏻  \[\033[00m\]\$ '
export PS1G='\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\e[1;38;2;0;255;0m ⏻  \[\033[00m\]\$ '

check-hsr() {
  [[ -f /var/run/reboot-required ]] && { export HSR=$(bc <<< "($(date +%s)-$(stat -c '%W' /var/run/reboot-required))/3600"); } || { export HSR=0; }
  [[ $HSR -ge 24 ]] && { export PS1=$PS1R; }
  [[ $HSR -ge 12 && $HSR -lt 24 ]] && { export PS1=$PS1Y; }
  [[ $HSR -lt 12 ]] && { export PS1=$PS1R; }
  [[ $HSR -eq 0 ]] && { export PS1=$PS1_NORM; }
};export -f check-hsr

# Use prompt_command to determine hours since reboot-required (HSR) and set the appropriate prompt
[[ ${PROMPT_COMMAND: -1} = ';' ]] && { export PROMPT_COMMAND+="check-hsr"; } || { export PROMPT_COMMAND+=";check-hsr"; }