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DVD ripping with ffmpeg
To rip DVD movie to ogg format using ffmpeg, follow these steps. 1) find the vob files on the mounted video DVD in VIDEO_TS that stores the movie itself. There would be a few other VOB files that stores splash screen or special features, the vob files for the movie itself can be identified by its superior size. You can verify these vob files by playing them directly with a player (e.g. mplayer) 2) concatenate all such vob files, pipe to ffmpeg 3) calculate the video size and crop size. The ogg video size must be multiple of 16 on both width and height, this is inherit limitation of theora codec. In my case I took 512x384. The -vcodec parameter is necessary because ffmpeg doesn't support theora by itself. -acodec is necessary otherwise ffmpeg uses flac by default.

Copy a file and force owner/group/mode
This is useful when you want to copy a file and also force a user, a group and a mode for that file. Note: if you want to move that file instead of copying it, you can use $install -o user -g group -m 755 /path/to/file /path/to/dir/ && rm -f /path/to/file which will remove the file only if the install command went fine.

show each new entry in system messages as a popup
It willl popup a message for each new entry in /var/log/messages found on the notify-send howto page on ubuntuforums.org. Posted here only because it is one of the favourites of mine.

Make sudo forget password instantly
By default sudo 'remembers' password for a few minutes, so that you do not need to re-enter password for a series of sudo commands that might follow within a short time duration. However, sometime you might want sudo to instantly 'forget' the password. (Next sudo command will need you to reenter the password) Credit: I first learned this while listening to one of the 'tuxradar' podcast.

Increase SCT of external USB disk enclosure to one hour.
So I had this 2TB Seagate external disk/USB enclosure which by default would spin-down its internal drive (it enters a standby mode) after four minutes of inactivity.. Spinning-up the inactive drive was an annoying delay when accessing files and also it severely interfered with NFS.. SCT stands for "Standby Condition Timer". To completely disable SCT: $ sdparm --clear STANDBY -6 /dev/sdb To return to original (default) SCT settings: $ sdparm -D -p 0x1a -6 /dev/sdb To verify the settings (before and after): $ sdparm -a /dev/sdb No need for vendor-provided MSWIN tools, etc.

Monitor logs in Linux using Tail
Works in Ubuntu, I hope it will work on all Linux machines. For Unixes, tail should be capable of handling more than one file with '-f' option. This command line simply take log files which are text files, and not ending with a number, and it will continuously monitor those files. Putting one alias in .profile will be more useful.

Rename files in batch

Dump dvd from a different machine onto this one.
You can use this to directly dump from machine A (with dvd drive) to machine B (without dvd drive) . I used this to copy dvd using my friend's machine to my netbook. Above command is to be issued on machine B. Advantages : 1) No wasting time dumping first to machine A and then copying to Machine B. 2) You dont need to use space on Machine A. In fact, this will work even when Machine A doesnt have enough hdd space to dump the DVD. Use -C ssh option on slow networks (enables compression). you can replace "dd if=/dev/dvd" with any ripping command as long as it spews the iso to stdout.

Edit a file on a remote host using vim

Remove all but one specific file


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