"git add" equivalent in svn?

You can give specific filenames and directories to svn commit via something like:

svn commit myfile.c

which will only commit that one file.

The svn commit command takes optional filename parameters that limit the set of files to commit:

svn commit -m "my commit" file1.txt file2.txt

You can also use the "changelist" feature to group one or more files into a changelist, which can be submitted in one command. This is still slightly less flexible than Git, because you can't add just a portion of a single file (such as with git add -p).