updates bash prompt

modules/bash/default.nix

@@ -5,6 +5,7 @@
 
     sessionVariables = {
       GPG_TTY = "$(tty)";
+      PROMPT_DIRTRIM = "3";
     };
 
     shellAliases = {
@@ -33,5 +34,13 @@
         source "$EMACS_VTERM_PATH"
       fi
     '';
+
+    initExtra = ''
+      if [ -n "$INSIDE_EMACS" ]; then
+        PS1="[\u@\h:\w]\\$ "
+      else
+        PROMPT_COMMAND="PS1_CMD1=$(git branch --show-current 2>/dev/null)'; PS1='\u@\h \[\e[96m\]\w\[\e[0m\] (\[\e[95m\]$PS1_CMD1\[\e[0m\])\n\[\e[96m\]λ\[\e[0m\] "
+      fi
+    '';
   };
 }