something about filter rules of rsync

[夏凯]

i want rsync to include all the *.dat files(and the *.dat files in the
subdirectory), and exclude all other files. how can i write the filter
rules? i have read the man rsync, but i still got no idea to do it.
for example, the result of find -printf "%y %p\n" is below:
d .
d ./1
d ./1/a
f ./1/a/a.c
f ./1/a/a.d
f ./1/a/a.dat
f ./1/a/b
f ./1/a.c
f ./1/a.d
f ./1/a.dat
f ./1/b
d ./2
how can i only rsync all the *.dat files from 1 to 2? is there any way
to do this without use find command?

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