An lsof Primer - Hackdot

Re:An lsof Primer by naner on Monday October 10, 2011 @01:55PM (#3094948)

The thing I use lsof for most often these days is watching Flash videos with mplayer (or VLC if you prefer). This allows me to pause/rewind/fullscreen easier. Or sometimes I save the file to watch later. You still have to start the video from within Flash and then pause it so it downloads the video file. Then you can do this:

    $ lsof | grep Flash
    plugin-co 1038   naner   16w   REG   254,2  4442164 7602188 /tmp/FlashXXfHeQqB (deleted)
    $ mplayer /proc/1038/fd/16

Oftentimes the output will give you duplicates for the same temporary flash file (FlashXXfHeQqB in this case) with an extra number after the process id, you can ignore all of that. I'm assuming those are child processes. All you need is the process id (1038) and the file descriptor (16). You can safely ingore the character (w) after the file descriptor.

Back in the day (Flash 9 or so?) the flash player used to just dump temporary flash video files in /tmp and delete them after you close the browser tab. I guess they figured it was too easy to copy the files out of /tmp so the newer flash player deletes the /tmp file immediately after it creates them. This is why we have to go and grab the open file descriptor.

This will work with most but not all websites. Some websites (Hulu) will use a streaming protocol (rtsp) among other things to make the content harder to get at outside of flash.

This works on Linux, I'm not sure about OSX or BSD.

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Re:An lsof Primer by ars on Monday October 10, 2011 @04:46PM (#3095756)

Try this script:

  #!/bin/sh

  IFS='\
  '
  for i in `ls -dLtr \`lsof -c plugin-containe -a -u $USER -X +L1 | awk -F ' +' '/\/tmp\/Flash/{ print "/proc/" $2 "/fd/" gensub("[^0-9]", "", "g", $4); }'\``; do
    PLAY="$PLAY $i"
  done
  IFS=' '
  mplayer -osdlevel 3 -fs $PLAY

I have it bound to a shortcut key in my window manager and I installed http://userscripts.org/scripts/show/13333 to automatically pick 720p videos, and pause them.

So I go to youtube in a tab, let it buffer for a bit, hit the shortcut key and enjoy.

Note that it's only semi-recent versions of flash that automatically delete the videos, if not remove the +L1

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Re:An lsof Primer by morsch on Monday October 10, 2011 @10:53PM (#3096866)

Just tried it. Consider my mind blown.

If you get an error relating to gensub ("function gensub never defined"), you need to install gawk.

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Re:An lsof Primer by thristian on Monday October 10, 2011 @11:13PM (#3096917)

For most Flash video hosting sites, clive¹ is the easiest way to download a video to watch in an external player; sometimes I've had to resort to poking through the HTML source in Firebug, but even that doesn't always yield a useful result. I'll have to keep lsof in mind the next time I hit one of those!

¹: http://clive.sourceforge.net/

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Re:An lsof Primer by mixmastamyk on Monday October 10, 2011 @02:40PM (#3095158)

Thanks. I also appreciate watching long presentations in an app such as VLC because I can then watch it at 1.2x or 1.5x speed to save time. After getting used to it a normal speed presentation seems to plod on forever.

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Re:An lsof Primer by rat on Tuesday October 11, 2011 @12:49AM (#3097155)

In linux at least you can use /proc/`ps -ef|grep flash|grep -v grep | awk {'print $2'}`/fd/

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