why it complains: Unmatched ".
 

On a RedHat 7, it complains

Unmatched ".

when I ran this command line:

sudo su - -c "R -e \"install.packages('shiny', repos='http://cran.rstudio.com/')\""


on both tcsh and bash. .. I wonder what was wrong? How can I get over this?

Thanks in advance! julian

Please use code tags when posting code or output.

You have double quotes within double quotes.
Try changing the outermost quotes to single quotes.

Thank you for the reply.

If I change outer pair of double quotes to single quotes, then it brings up problems with other single quotes in the command line, causing
I just got over this simply by su to root, fire up an R, and ran the command line within the R environment.

I would like to follow this problem because it's copied command line from a tutorial, which imply it worked for many others. I just wonder why it didn't work in my bash/tcsh on RH7.

first of all you do not (must not) use sudo and su together, most probably sudo is the [only] one you need.
Next: if you have a situation like this (quotation problems) try to write a working shell script (without sudo) and finally just sudo <your script> will do the job.

It is not bash/tcsh and/or RH7, but incorrectly formulated command. (probably you made a mistake when you copied it from that tutorial). By the way which tutorial is it?

finally you may find shellcheck.net useful to catch this issue.

I agree with pan64's suggestion of placing in a script, but if you do still want to use varying types of quotes, I would suggest you look into heredocs

Then, as the line is already using single quotes too, he would have single quotes within single quotes, not a real improvement :-(

I see I didn't study it carefully enough. I was going for '..."...'...'..."...' - such that the second set of singles were inside the doubles, which should be OK, theoretically.