If you want to change the svn credentials permanently. i.e from now onwards if you want the code to be commited using 'newUser@abc.com' svn-account everytime, so instead of using the --username and --password switch everytime, we can just remove the old svn account and configure the new svn account as the default account for any svn changes from now onwards.
For this, we need to remove the previously saved svn credentials from your system.
By default the svn credentails are stored in a hidden directory named as 'subversion/auth' in your home folder. If you open up the svn.simple directory inside 'auth' you will see a file inside it which contains the current svn username and password that is configured on your system. We need to remove it.
You can remove the entire 'auth' directory for this, using the following command in your terminal
$rm -rf ~/.subversion/auth
After this the old credentials will be removed from your system. and when you take svn update for the next time using
It will prompt you for the new svn username and password. And those would be automatically saved in your system in the files mentioned above. And from now onwards it will act as the default svn username & password.
Write system password ============> 123456
new username =========> newUser@abc.com
new password =========> 123456