1 files changed, 9 insertions, 6 deletions
diff --git a/bib-convert b/bib-convert
index ef4c0b0..fc215b7 100755
--- a/bib-convert
+++ b/bib-convert
@@ -40,12 +40,15 @@ trap 'rm -f "$tmp"' EXIT INT TERM
 cat "$@" > "$tmp"
 
 if [ "$mode" = auto ]; then
-  first=$(awk 'NF { sub(/^[ \t]+/, ""); print substr($0, 1, 1); exit }' "$tmp")
-  case $first in
-    @) mode=toref ;;
-    %) mode=tobib ;;
-    *) printf 'bib-convert: cannot detect input format\n' >&2; exit 1 ;;
-  esac
+  # first line that is unambiguous wins: an @entry means bibtex, a
+  # %X field means refer (a bare "% comment" decides neither)
+  mode=$(awk '
+    /^[ \t]*@/ { print "toref"; exit }
+    /^%[A-Z] / { print "tobib"; exit }' "$tmp")
+  if [ -z "$mode" ]; then
+    printf 'bib-convert: cannot detect input format\n' >&2
+    exit 1
+  fi
 fi
 
 if [ "$mode" = toref ]; then