Someone on the MacNN Forums asked about doing timed repetitive screen captures. To set up a script that takes a screenshot of your desktop every hour, use the following Applescript. Note that "¬" is Apple's line continuation character; type it by hitting option-enter on your keyboard. Here's the script:
set save_location to ¬Note that you can change the loop to whatever you want. You can even make it indefinite and specify a time to quit if you want. Read up on Applescript as there are lots of cool things like this you can do.
(choose folder with prompt "Choose where to save screenshots")
repeat with shotcount from 1 to 100
do shell script "screencapture " & ¬
quoted form of POSIX path of save_location ¬
& "screen" & (shotcount as string) & ".pdf"
delay (60 * 60) -- delay one hour
end repeat
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