It's possible to make Subversion ignore unversioned files, so they don't show up in the status overview and you get a better signal to noise ratio. The command line interface to add ignore rules this is however a bit clunky. First, you need to remember following command:

svn propedit svn:ignore .

(which can be quite confusing, especially with the slightly similar looking but different propset command). Then you get a file editor where you have to add the rule (make sure you remembered the file name or pattern you want to ignore), save the file and exit the editor. A bit too much hoops to jump through for something that could be just one command like svn-ignore filename.

I wrote this simple python script to get this functionality:

#!/usr/bin/env python

"""
Script to make it easier to add svn-ignore rules.
"""

import sys
import os
import subprocess

def svn_propget_svnignore(path):
    '''fetch the svn:ignore property of given path'''
    p = subprocess.Popen(['svn', 'propget', 'svn:ignore', path], stdout=subprocess.PIPE)
    p.wait()
    data = p.stdout.read().strip()
    return data

def svn_propset_svnignore(path, value):
    '''set the svn:ignore property of the given path'''
    p = subprocess.Popen(['svn', 'propset', 'svn:ignore', value, path])
    p.wait()


def main():

    if len(sys.argv) < 2:
        print 'Usage: %s filenames' % sys.argv[0]
        sys.exit()

    for path in sys.argv[1:]:
        print path

        dirpath, filename = os.path.split(path)
        svnignore_data = svn_propget_svnignore(dirpath)

        if filename not in svnignore_data.split('\n'):
            svnignore_data += '\n' + filename
            svn_propset_svnignore(dirpath, svnignore_data)

if __name__ == '__main__':
    main()

I saved it as svn-ignore.py, made it executable, put it somewhere in my PATH and now I can just do

svn-ignore.py foo.txt bar.zzs "*.backup"

Note that it also supports wildcard rules, but these have to be put in quotes, so the shell does not expands them.