Ignore file

To ignore all files with the ending .o use:

svn propset svn:ignore "*.o" .

Ignore dir

If you want to ignore folder {tmp}

svn propset svn:ignore tmp .

Ignore multiple files/dirs

If you want to ignore {tmp,obj,bin} dirs and all files with {.o *.lib,.la} extension. Save this file

tmp
obj
bin
*.o
*.lib
*.la

and name it {svnignore.txt}, the following command will do the job !

svn propset svn:ignore -F svnignore.txt .

Ignore multiple files/dirs via command line

svn propedit svn:ignore .

This will bring up list of files or directories to ignore.

Find files that are not under version control

To find such files:

svn status | grep ^\? | awk '{print $2}'