let vcftools =
  installable_tool Machine.Tool.Default.vcftools
    ~url:"http://downloads.sourceforge.net/project/vcftools/vcftools_0.1.12b.tar.gz"
    ~install_program:(fun ~path -> KEDSL.Program.(
        sh "make"
        && shf  "cp -r bin %s" path
        && shf  "cp -r lib/perl5/site_perl %s" path
      ))
    ~witness:(witness_file @@ "bin" // "vcftools")
    ~init_program:(fun ~path ->
        KEDSL.Program.(shf "export PATH=%s/bin/:$PATH" path
                       && shf "export PERL5LIB=$PERL5LIB:%s/site_perl/" path))