On Windows, the `exec` option does not correctly escape the output parameter unless the `restrict-filenames` option is given.

[SteffanDonal]

• I've verified and I assure that I'm running youtube-dl 2016.08.07
• At least skimmed through README and most notably FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones

What is the purpose of your issue?

• Bug report (encountered problems with youtube-dl)

When running without restrict-filenames

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['-v', '--exec', 'echo {}', 'https://www.youtube.com/watch?v=0c1nUVlqzdY']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2016.08.07
[debug] Python version 3.4.4 - Windows-10-10.0.10586
[debug] exe versions: ffmpeg N-80256-g0a9e781, ffprobe N-80256-g0a9e781
[debug] Proxy map: {}
[youtube] 0c1nUVlqzdY: Downloading webpage
[youtube] 0c1nUVlqzdY: Downloading video info webpage
[youtube] 0c1nUVlqzdY: Extracting video information
[youtube] 0c1nUVlqzdY: Downloading MPD manifest
WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[download] G.A.B.E. - 'Hydrodogs' Full song-0c1nUVlqzdY.mkv has already been downloaded and merged
[exec] Executing command: echo 'G.A.B.E. - '"'"'Hydrodogs'"'"' Full song-0c1nUVlqzdY.mkv'
'G.A.B.E. - '"'"'Hydrodogs'"'"' Full song-0c1nUVlqzdY.mkv'

When running with restrict-filenames

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['-v', '--exec', 'echo {}', '--restrict-filenames', 'https://www.youtube.com/watch?v=0c1nUVlqzdY']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2016.08.07
[debug] Python version 3.4.4 - Windows-10-10.0.10586
[debug] exe versions: ffmpeg N-80256-g0a9e781, ffprobe N-80256-g0a9e781
[debug] Proxy map: {}
[youtube] 0c1nUVlqzdY: Downloading webpage
[youtube] 0c1nUVlqzdY: Downloading video info webpage
[youtube] 0c1nUVlqzdY: Extracting video information
[youtube] 0c1nUVlqzdY: Downloading MPD manifest
WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[download] G.A.B.E._-_Hydrodogs_Full_song-0c1nUVlqzdY.mkv has already been downloaded and merged
[exec] Executing command: echo G.A.B.E._-_Hydrodogs_Full_song-0c1nUVlqzdY.mkv
G.A.B.E._-_Hydrodogs_Full_song-0c1nUVlqzdY.mkv

Description

I'm attempting to do some basic automation to pass converted videos through to another script - however the {} replacement is not correctly escaped for a Windows environment. I can work around it by using the restrict-filenames switch (and some manually-placed quotes), however I'd like to not need to do this as the functionality is there.

Happy to help out with the development required for this issue, any preferences for how it should be fixed?