Redmine

http://www.redmine.org/projects/redmine/wiki/HowTo_Easily_integrate_a_(SSH_secured)_GIT_repository_into_redmine

*/5 * * * * redmine cd /var/lib/redmine/repos/my_repo && git fetch --all

let above line text write into /etc/crontab,but no change.using commend "git pull" -all is ok.why?