Allow running Rscript via rig subcommand

[klmr]

Rig has a subcommand rig run to run a specific version of R with arguments.

It would be great if there was a similar way of running Rscript, e.g.:

rig run --script -r devel ‹file›
rig script -r devel -e ‹expr›

[gaborcsardi]

@klmr Thanks! Since you probably know this already, can you remind me what the benefits of Rscript are over R -f?

[klmr]

The benefit/difference is that Rscript doesn’t echo the executed code, so it behaves like most other mainstream scripting language interpreters in non-interactive (perl, ruby, python …) in this regard.

I don’t know why R -f does this, and maybe there are use-cases. But for self-contained command line utilities this is pretty much never the expected behaviour (notably, it makes programmatic processing of the output much harder).

Cf.:

$ R -e 'cat("hello\n")'
> cat("hello
+ ")
hello

$ Rscript -e 'cat("hello\n")'
hellp

[gaborcsardi]

OK, makes sense. I guess you'd need to suppress the echo explicitly:

❯ R -s -q -e 'cat("hello\n")'
hello

But we can have (probably)

rig run --script -r devel ‹file›

[klmr]

Regarding the -q option: the most important use-case for Rscript is probably in shebang lines of executable scripts: (for reasons I don’t understand) shebang lines limit the number of arguments you can pass portably, so you couldn’t have a shebang line that specifies the arguments -q -f (actually you can’t even pass a single argument).

But that’s of course irrelevant for usage via rig run.