zsh: redo shell prompt, use OS specific icon in prompt

stow/.zshrc

@@ -1,6 +1,24 @@
 # z shell configuration
 
-PROMPT="%F{green}%~ %F{yellow}%m %f"
+export OSICON="?"
+
+if [ -e /System ]; then 
+  OSICON=""
+else
+  . /etc/os-release &> /dev/null
+
+  if [ "$ID" = "nixos" ]; then
+    OSICON=""
+  elif [ "$ID" = "debian" ]; then
+    OSICON=""
+  elif [ "$ID" = "fedora" ]; then
+    OSICON="󰣇"
+  elif [ "$ID" = "arch" ]; then
+    OSICON=""
+  fi
+fi
+
+PROMPT="%K{blue}%F{black} %~ %K{yellow} $OSICON %k "
 
 bindkey -e