Use bash and makefile to generate report.
make do make clean
#> .
#> +-- do.R
#> +-- files.sh
#> +-- hello.R
#> +-- input
#> | \-- gl.csv
#> +-- makefile
#> +-- makefile.Rproj
#> +-- process.txt
#> +-- README.md
#> +-- README.Rmd
#> \-- report.Rmd