# ---------------------------------------------------------------------
#      Ignore all the .txt files in the /trunk/Blah/ directory
# ---------------------------------------------------------------------

# Go to the directory
cd trunk/Blah/              # The directory with the files

# Start editing the properties for the current directory
svn propedit svn:ignore .   # Opens an editor (SVN_EDITOR, EDITOR)

# Add the following value with a new line, save, and exit:
*.txt

# See that things worked
svn propget svn:ignore .    # So you can see the properties
svn status --no-ignore      # You should see an 'I' next to the ignored files

# Commit
svn commit -m "New Ignores" # You must commit the new property change