How do I turn a command line into a shell script?

Through an eerie coincidence, I too have been going through that same task, converting movies to dump onto my new Blackberry Pearl, which actually does quite a good job with video, rather to my surprise! It's not much bigger than a postage stamp, but it's watchable, and heck, it's a cellphone... :-)

Anyway, the information I found on using mencoder is from the8thsign.com. If you're on a PC, then you might find this posting in Pinstack.com's Blackberry forums useful.

The command I used is:

Scary, isn't it? No wonder you're looking for a way to avoid typing that in each time you want to convert a movie!

Fortunately, it's a very regular pattern and that means that it's not hard to replace "input" and "output" with specific variables and just prompt for those values when the script is started. That's exactly what the following script does:

Save this as, say, "convert-movies", make it an executable with the command chmod +x convert-movies, and now you can just type "convert-movies" to get the script running:

Nice, simple, and far easier to remember. Note that I already knew the name of the input file, so you can't use filename completion as you could on the command line (in fact, it would be pretty easy to add the ability to specify the input and/or output filenames on the command line itself, allowing you to type in "convert-movie bourne-identity.avi bourne-identity-out.avi" or similar. I'll leave that as an exercise for you, dear reader, however!)