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More recent versions of the date command finally have the ability to decode the unix epoch time into a human readable date. This function makes it simple to utilize this feature quickly.
-i = input file name
-s = set frame size, qcif=176x144
-vcodec = force video codec
-r = frame-rate [default = 25]
-b = bit-rate [200 kb/s]
-acodec = force audio codec
-ab = audio bitrate in bits/s [64k]
-ac = no. of audio channels 
-ar = audio sampling frequency [44100 Hz]
-sameq = use same video quality as source (implies VBR)
-f = force format
-y = overwrite output files
just a bit simpler
In this example we convert a .tar.bz2 file to a .tar.gz file.
If you don't have Pipe Viewer, you'll have to download it via apt-get install pv, etc.
A shell function using perl to easily convert Unix-time to text.
Put in in your ~/.bashrc or equivalent.
Tested on Linux / Solaris Bourne, bash and zsh. using perl 5.6 and higher.
(Does not require GNU date like some other commands)
Convert those .mov files that your digital camera makes to .avi
Adjust the bitrate (-b) to get the appropriate file size. A larger bitrate produces a larger (higher quality) .avi file and smaller bitrate produces a smaller (lower quality) .avi file.
Requires ffmpeg (see man page for details)
(tested with canon camera MOV files)
ffmpeg -i input.mov -sameq -vcodec msmpeg4v2 -acodec pcm_u8 output.avi
ffmpeg -i input.mov -b 1024k -vcodec msmpeg4v2 -acodec pcm_u8 output.avi
Doesn't fail for percent sign now.
I've corrected the function. My octal conversion formula was completely wrong. Thanks to pgas at http://mywiki.wooledge.org/BashFAQ/071 for setting me straight. The new function is from pgas and is very fast.
This converts any media ffmpeg handles to flash. It would actually convert anything to anything, it's based on the file extension. It doesn't do ANY quality control, sizing, etc, it just does what it thinks is best. I needed an flv for testing, and this spits one out easily.
Whereas ^V is CTRL-V.
converts a dos file to unix by removing 0x13 characters
Resizes all images in the curent directory to x resolution.
It is better than `mogrify -resize *.jpg` because of independence from extension of image (e.g. .jpg and .JPG) (: