updated for version 7.4.191
Problem: Escaping a file name for shell commands can't be done without a
function.
Solution: Add the :S file name modifier.
diff --git a/runtime/doc/vi_diff.txt b/runtime/doc/vi_diff.txt
index 45fe7de..aadbf9b 100644
--- a/runtime/doc/vi_diff.txt
+++ b/runtime/doc/vi_diff.txt
@@ -540,7 +540,7 @@
Added :wnext command. Same as ":write" followed by ":next".
The ":w!" command always writes, also when the file is write protected. In Vi
-you would have to do ":!chmod +w %" and ":set noro".
+you would have to do ":!chmod +w %:S" and ":set noro".
When 'tildeop' has been set, "~" is an operator (must be followed by a
movement command).