今天一朋友来问我usermod -l的用法，自己也不太清楚，就MAN了一下 SYNOPSIS usermod [options] LOGIN -l, --login NEW_LOGIN The name of the user will be changed from LOGIN to NEW_LOGIN. Nothing else is changed. In particular, the user's home directory name should probably be changed to reflect the new login name. 结果我按他的说明来操作了，但出现错误 usermod -l 用户名（系统已经存...