错误描述pipinstallrequirements.txtDefaultingtouserinstallationbecausenormalsite-packagesisnotwriteableERROR:Couldnotfindaversionthatsatisfytherequirements.txt(fromversions:none)ERROR:Nomatchingdistributionfoundforrequirements.txtvagrant@vagrant:/vagrant$sudopipinstallrequirements.txt解决方法是缺少-r参数，替换为如下命令pipinstall-rrequirements.txt
