Shell script not setting variables

I'm /bin/sh as the shell for this script. I'm attempting to create a script that will automate the ripping of DVDs into a format to be named later. So far, I'm able to take the output of Mplayer/mencoder and create a file called "crop.txt".

when I run the script, though, crop.txt is created, but the variables I want to set don't get set...

what am I doing wrong? I'm sure it's something very minor...

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#!/bin/sh

mplayer -v -ss 00:15:00 -frames 20 -vf cropdetect dvd://1 > crop.txt

CROP='tail -n 11 crop.txt | grep CROP | cut -d= -f2 | cut -c 1-11'
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now, I've run these commands independently, and the output from

"tail -n 11 crop.txt | grep CROP | cut -d= -f2 | cut -c 1-11"

is "720:480:0:0". I want this set as $CROP, so that later in the script, I can call that variable.

Any assistance is greatly appreciated...

Please keep the scope to only /bin/sh. I have no interest in using csh, bash, or anything like that... /bin/sh is ubiquitous to all UNIX systems.

Bryan

If you are going to run commands and assign the output to a variable you need to make sure you use the right quotes. ( i.e. the ones on the tilde[~] key ) I can't remember what they're actually called.. but here's your example with the correct quotes.

CROP=`tail -n 11 crop.txt | grep CROP | cut -d= -f2 | cut -c 1-11`

also, you can always run your script in debug mode to watch these things.

sh -x ./script.sh

or change the shebang to

#!/bin/sh -x