SVN Commit Failed

Today when I tried to commit from Terminal, I have got this message:

“svn: None of the environment variables SVN_EDITOR, VISUAL or EDITOR is set, and no ‘editor-cmd’ run-time configuration option was found”

But svn checkout, status and update are working. I did some research and found that I can get around this by using -m parameter

svn ci -m “message”

And again, it works.