我尝试在错误的Ubuntu 16.04 VM中安装devtools软件包。
我成功尝试安装的其他软件包
但是我无法安装它，控制台中的过程是这样的：
> install.packages("devtools")
Installing package into ‘/home/stefan/R/x86_64-pc-linux-gnu-library/3.2’
(as ‘lib’ is unspecified)
also installing the dependencies ‘curl’, ‘openssl’, ‘httr’, ‘git2r’
--2018-01-26 22:14:08-- https://cran.rstudio.com/src/contrib/curl_3.1.tar.gz
Resolving cran.rstudio.com (cran.rstudio.com)... 54.230.27.181
Connecting to cran.rstudio.com (cran.rstudio.com)|54.230.27.181|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 366086 (358K) [application/x-gzip]
Saving to: ‘/tmp/RtmpIF4wAz/downloaded_packages/curl_3.1.tar.gz’
0K .......... .......... .......... .......... .......... 13% 1017K 0s
50K .......... .......... .......... .......... .......... 27% 1,62M 0s
100K .......... .......... .......... .......... .......... 41% 1,32M 0s
150K .......... .......... .......... …