Add Filename.quote_command function (#1492)

MPR#7672: add a Filename.quote_command function

This function takes care of quoting the command and its arguments
so that they are correctly parsed by the system shell
(/bin/sh for Unix, cmd.exe for Win32).

Redirections for std input (< file) and std output (> file) and
std error (2> file) can also be specified as optional arguments.
A 2>&1 redirection is used if stdout and stderr are redirected to the
same file.

The result is a string that can be passed directly to Sys.command or
to the Unix functions that expect shell command lines.

1 files changed, 4 insertions, 0 deletions

diff --git a/Changes b/Changes
index bc485a5daa..c3686b9272 100644
--- a/Changes
+++ b/Changes
@@ -63,6 +63,10 @@ Working version
    (Jacques-Henri Jourdan, review by Stephen Dolan, Gabriel Scherer and
     Damien Doligez)
 
+- #7672, #1492: Add `Filename.quote_command` to produce properly-quoted
+  commands for execution by Sys.command.
+  (Xavier Leroy, review by David Allsopp and Damien Doligez)
+
 ### Other libraries:
 
 - #1939, #2023: Implement Unix.truncate and Unix.ftruncate on Windows.