Added helper script for analyzing simple errors

huhh.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+EXPR_MSG="evaluating derivation"
+PROP_MSG="of derivation"
+
+LOC=$1
+if [ -z $1 ]; then
+  exec {1}<>"$LOC"
+fi
+
+ERROR_LINE=$(<$LOC grep -nF "error:" \
+  | tail -n1 \
+  | awk '{print substr($1,1,length($1)-1)}' )
+<$LOC sed -n "$ERROR_LINE,\$p"
+
+echo "[*] Reason:"
+<$LOC grep "evaluating attribute '.*' of derivation" \
+  | awk '{ print substr($NF, 2, length($NF)-2), substr($5, 2, length($5)-2)}'