有关如何安装R统计软件包devtools的任何建议吗？
>install.packages("devtools",repos="http://cran.rstudio.com", type = "source")
Installing package into ‘/home/bckadm/nowackj1/R/x86_64-unknown-linux-gnu-library/3.0’
(as ‘lib’ is unspecified)
Warning message:
package ‘devtools’ is not available (for R version 3.0.1)
>