Disabling IPv6 on MAC OSX:

networksetup -setv6off Wi-Fi

To enable again:

networksetup -setv6automatic Wi-Fi

Animating images

Create an animation (movie) from a sequence of images:

ffmpeg -f image2 -r 1 -i filename-%04d.png -s WxH -f mpeg -r 24 foo.mpg
  • replace WxH with width and height (ex: 800x600)
  • The first -r1 makes the video 1 fps (input), so you can speed up/down as necessary.
  • mpeg format seems to work okay with powerpoint.

Create a tar archive over ssh

Creating an archive of a remote directory over SSH:

ssh <host> "tar czf - /remote/directory/" > output.tgz


ssh you@hostname "tar czpf - /path/to/directory/" > local-file.tgz