I want my password to be forgotten, so I have to type it again.
I have setup this:
git config credential.helper \'cache --timeout=600\'
Problem 1: "want my password to be forgotten" by git
Problem 2 (implied): contradictory configuration settings
Answer:
git config --unset-all credential.helper
git config --global --unset-all credential.helper
git config --system --unset-all credential.helper
Explanation: Git configuration is specified in three places:
The commands noted above will remove all settings related to credentials at the repository, user and system level... which (I think) answers your question.
However, it sounds like your problem may be limited to having some sort of configuration contradiction related to one option of credential.helper, cache. If you'd prefer to reset only that option, do this:
git config --unset credential.helper 'cache'
git config --global --unset credential.helper 'cache'
git config --system --unset credential.helper 'cache'
... then set the timeout at the appropriate level, any of:
git config --set credential.helper 'cache --timeout=600'
git config --global --set credential.helper 'cache --timeout=600'
git config --system --set credential.helper 'cache --timeout=600'
For more, see the excellent documentation here: