1 files changed, 11 insertions, 9 deletions
diff --git a/Master/tlpkg/TeXLive/TLWinGoo.pm b/Master/tlpkg/TeXLive/TLWinGoo.pm
index edffe918757..b1cfe76d1ea 100644
--- a/Master/tlpkg/TeXLive/TLWinGoo.pm
+++ b/Master/tlpkg/TeXLive/TLWinGoo.pm
@@ -286,17 +286,19 @@ values as environment variable and returns the result.
 
 =cut
 
+sub expand_env {
+  my $key = shift;
+  foreach my $k (keys %ENV) {
+     return $ENV{$k} if (uc($k) eq uc($key));
+  }
+
+  return "%$key%";
+}
+
 sub expand_string {
   $s = shift @_;
-  while ($s =~ /^([^%]*)%([^%]+)%(.*)$/) {
-    foreach $k (keys %ENV) {
-      if (uc($k) eq uc($2)) {
-        $s = $1 . $ENV{$k} . $3;
-        last;
-      }
-    }
-  }
-  $s;
+  $s =~ s/%([^%;]+)%/expand_env($1)/eg;
+  return $s;
 }
 
 =pod