Add Relative Filepaths section for setting FZF_DEFAULT_COMMAND

Windows.md

@@ -6,6 +6,20 @@ flawlessly.
 [bin]: https://github.com/junegunn/fzf-bin/releases
 [wsl]: https://blogs.msdn.microsoft.com/wsl/
 
+### Relative Filepaths
+
+fzf uses `dir /s/b` as its default command for performance but it outputs absolute filepaths.
+To use relative filepaths, set `FZF_DEFAULT_COMMAND` to any of the following and run it cmd.exe because it is faster than powershell.exe:
+
+- cmd.exe https://github.com/junegunn/fzf/pull/971#issuecomment-313971408
+```dosbatch
+cmd.exe /q/V:ON/c "for /f %A in ('dir /s/b 2^> nul') do set RELPATH=%A & echo !RELPATH:%cd%\=!"
+```
+- powershell https://github.com/junegunn/fzf/issues/960
+```dosbatch
+powershell.exe -NoLogo -NoProfile -Noninteractive -Command "Get-ChildItem -File -Recurse -Name"
+```
+
 ### PowerShell support
 
 https://github.com/kelleyma49/PSFzf