Tar: avoid archiving of files larger than certain size

I want to archive files (with tar) which are below 3 MB in size. But I also want to retain the directories in which those files exist. (so I cannot use find command). I just want to avoid the files which are above 3 MB in size. How can this be done?

Simpler than you think:

$ tar cf small-archive.tar /big/tree --exclude-from <(find /big/tree -size +3M)

On a semi-related note (relating to your statement that you can't use find) to get a listing of all files (including directories) under a path minus files larger than 3MiB, use:

$ find . -size -3M -o -type d

You could then do:

$ tar cf small-archive.tar --no-recursion --files-from <(find /big/tree -size -3M -o -type d)

But I'd prefer the first one as it's simpler, clearly expresses what you want and will lead to less surprises.

If the filename contains square brackets, in some systems, need to exclude explicitly. For example

$ mkdir test
$ echo "abcde123456" > ./test/a[b].txt
$ echo "1" > ./test/a1.txt
$ ls -la ./test
total 16
drwxrwxr-x 2 user user 4096 Jan 10 16:38 .
drwx------ 4 user user 4096 Jan 10 16:38 ..
-rw-rw-r-- 1 user user    2 Jan 10 16:38 a1.txt
-rw-rw-r-- 1 user user   12 Jan 10 16:38 a[b].txt
$ tar -zcvpf a.tar.gz ./test
./test/
./test/a[b].txt
./test/a1.txt
$ tar -zcvpf a3.tar.gz ./test --exclude-from <(find ./test -type f -size +3c)
./test/
./test/a[b].txt
./test/a1.txt
$ tar -zcvpf ax.tar.gz ./test --exclude-from <(find ./test -type f -size +3c) --exclude '*\[*'
./test/
./test/a1.txt