@palica, You're quite right. I can use pre-existing /var/git/meta-repo in many ways.
The oneliner should be
cd /var/git/meta-repo/repos.conf; for i in *;do ln -s /var/git/meta-repo/repos.conf/$i /etc/portage/repos.conf/ego-$i;done
By the way, what meaning does the 'ego-' prefix have?
And I have to check meta-repo's change periodically and update links and so on, don't I?
Thank you :)