ALL Git* => Gitlab

• Nothing, Just copy the git URL to gitlab（类似于 fork）
• 使用 Git Mirror 無痛轉移 Git Server

SVN => Gitlab

• Migrating from SVN to GitLab
• The simple method

Gitlab => GitHUB / ALL Git*

• 如何从gitlab迁移到github - SegmentFault
• 如何从Gitlab顺利迁移到Github | Git

Git* <=> Git*

• Duplicating a repository - GitHub官方提供

Additions

• Creating a new repository With License
• Getting Started With Git
• A simple way to create git repository on a server machine
• 【官方标准Git教程！！！】Git on the Server - Setting Up the Server