不小心参考了:
运行了:sudo apt-add-repository ppa:rockclimb/gephi-daily
结果在apt-get update的时候报错:
W: Failed to fetch http://ppa.launchpad.net/rockclimb/gephi-daily/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/rockclimb/gephi-daily/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
略坑的。要还原原来的样子,需要移除刚刚添加的PPA源: