ADDED   fish/functions/flgrep.fish
Index: fish/functions/flgrep.fish
==================================================================
--- fish/functions/flgrep.fish
+++ fish/functions/flgrep.fish
@@ -0,0 +1,8 @@
+function flgrep
+    set -l ret
+    fossil changes --all . | sed 's/^.*  //' | while read file
+        grep -H $argv "$file" && set ret 0
+        test $status -gt 1 && return $status
+    end
+    return $ret
+end