Need a unix command

Question

Hi all,
I just can't figure this out... I need a unix command that will backup any file matching a specific file extension AND the directory structure those files are in into a separate directory or volume. In other words, let's say that I have the files and directory structure below. I want to backup all of the txt files as separate files (not a tar archive) without writing the img files, without overwriting one txt file with another, and preserving the directory structure.
foo/bar/a.txt
foo/bar/b.txt
foo/bar/a.img
foo/bar/b.img
foo/me/a.txt
foo/me/b.txt
foo/me/a.img
foo/me/b.img
foo/me/you/a.txt
foo/me/you/b.txt
foo/me/you/a.img
foo/me/you/b.img
I've read the man pages for ditto and rsync... they're geared toward backing up every file in a directory, and so they're not very clear about how to backup one single file type/extension.
Everytime I try different varients of the rsync command, I either get errors "rsync error: some files could not be transferred (code 23) at /SourceCache/rsync/rsync-24.1/rsync/main.c(717)", or file not found, or it overwrites the 'a.txt' with a different 'a.txt' without preserving the directory structure.
Can someone give me the exact syntax for backing up the .txt files in the example above to an external disk (e.g. /Volume/backup)???
Thanks!

Answer 1

OK... my example was oversimplified. There are tons of different types of files in my directories (*.img, *.gif, *.etc), and I only want to cp one type (e.g., .txt).
So, I started with the --include flag using the following command:
rsync -nav --include *.txt foo/ /Volumes/baz/
the result listed every file in foo (e.g., *.txt, *.img)
I thought that perhaps the \*.txt should be *.txt
rsync -nav --include *.txt foo/ /Volumes/baz/
the result listed every file in foo (e.g., *.txt, *.img)
rsync -nav --include "*.txt" foo/ /Volumes/baz/
again, the result listed every file in foo (e.g., *.txt, *.img)
Clearly, the --include flag wasn't working as I expected it to work. So, I decided to try the --exclude flag:
rsync -nav --exclude "*.img" foo/ /Volumes/baz/
Now, the results listed every file in foo except the *.img files.
I needed to exclude other files as well, so I tried:
rsync -nav --exclude "*.img *.etc" foo/ /Volumes/baz/
Now, the results listed every file in foo INCLUDING the *.img files. So, adding additional file types within quotes broke the original command.
rsync -nav --exclude *.img *.etc foo/ /Volumes/baz/
Now, I get the error "rsync: link_stat "/Volumes/HD/foo/*.etc" failed: No such file or directory (2)"; and all .etc files are still included
Now I tried:
rsync -nav --exclude *.img --exclude *.etc foo/ /Volumes/baz/
Now, this excluded both *.img and *.etc files. I have about 20 file types other than *.txt ... there has to be some other way!!!
PowerMac Dual 2.7GHz G5 Mac OS X (10.4.9) 4.5GB RAM