Problem with find excluding files of type socket when creating tar archive

Question

I am trying to make a tar archive of all files in my /var directory. Naturally, I want to exclude the Unix sockets in there.

So I try a command that looks something like:

sudo find /var \! -type s -exec tar -rf ~/test/etc.tar {} \;

But this throws up the repeated error message

tar format cannot archive socket:

When I try to do a copy instead of tar, I get a similar error:

cp: ./var/run/devd.pipe is a socket (not copied).

Does anyone have an idea why find fails to exclude files of type socket? It is able to exclude, for instance, files of type directory..

Answer 1

You will have to exclude directories as well. If not excluding directories, tar will get /var (and other directories) as argument, and will proceed to archive these with all contents (sockets or not). It will additionally add multiple copies of many of the files due to the same reason (/var includes /var/log/messages and so does /var/log).

find /var ! -type s ! -type d -exec tar -r -f archive.tar {} +

Or, if you just want regular files and symbolic links:

find /var '(' -type f -o -type l ')' -exec tar -r -f archive.tar {} +

I've chosen to use -exec ... {} + here instead of -exec ... {} ';' as we probably want to call tar as few times as possible with as many arguments as possible at a time.