I have a security system that FTPs the camera files to my machine, however I want to sort the pictures (taken every 30s) into directories by hour.

Every picture uses the following file format.
yymmddhhmmsstt.jpg (where tt is the milliseconds)

I am thinking the for loop is best

for file in *.jpg
do
?here?
done

I know its very vague, however the end result is I am guessing use awk (or better?) to create variables from the yy mm dd hh parts of the filenames, then creating directories based on those variables nested with a check to see if the directory exists, creating the directory if it doesnt.

i.e. (the way I imagine it working, I dont know how to actually construct the script to do this)

for file in 08072400123200.jpg
do
%y=08
%m=07
%d=24
%h=00
if not exist directory %y - mkdir %y
if not exist directory %y/%m - mkdir %y/%m
if not exist directory %y/%m/%d - mkdir %y/%m/%d
if not exist directory %y/%m/%d/%h - mkdir %y/%m/%d/%h
mv %y%m%d%h*.jpg %y/%m/%d/%h
done

Moving all the pictures taken within that hour into the respective subdirectories.

Any help would be much appreciated.