R package development best practices: using system() command? - r

Question

I'm developing a new R package to release to CRAN and would like to invoke the system() command directly within its source code. For example, I would like to use the gzip utility directly within my R package:
write.csv(mydat, "mydat.csv")
system("gzip mydat.csv", wait=FALSE)
Even more importantly, I would like to leverage other existing command-line utilities directly within my R package. And by command-line utilities, I mean actual large command-line software programs that are not trivial to rewrite in R.
So my question is: What are some best practices for specifying the usage of external (not R) command-line libraries during the development of an R package?
For example, the Imports and Depends fields in an R package DESCRIPTION file are only good for specifying the usage of existing R libraries within your R package. It would be a nuisance for users to have to manually install some existing non-R command-line library by using a package manager (e.g., brew), and this would go against best practices of self-contained work within an R Studio IDE. Besides, there is no guarantee that such a roundabout approach would work in a reproducible fashion, due to the difficulty of properly matching full paths to the command-line executable, coordinating with the R Studio IDE, etc.
Likewise, using tools such as https://cran.r-project.org/web/packages/ssh.utils/index.html will only serve basic command-line needs within the R environment, and hence does not apply to the needs of using large command-line software programs.
Note: The R package that I'm developing is not for personal use. It is intended for public release to CRAN and, hence, should comply with their checks. However, I could not find any specification from CRAN regarding the use of the system() command, particularly in the context of leveraging actual large command-line software programs that are not trivial to rewrite in R.

Answer 1

I would like to use the gzip utility directly within my R package
That is a code smell. Your package then needs to determine by means of configure (or similar) if such programs exist. So why bother? In this example, and on my box:
edd#don:~$ grep GZIP /etc/R/Renviron
R_GZIPCMD=${R_GZIPCMD-'/bin/gzip -n'}
edd#don:~$
You have access to it via most file-saving commands such as saveRDS(), the gzcon() and gzfile() functions and so on. See this older answer of mine.
For truly external programs you can rely on system(). See Christoph's seasonal package relying on our underlying x13binary binary package.