r - What is the process to allocate certain amount of the RAM to Rstudio on Ubuntu - Ask Ubuntu

as ubuntu beginner, question managing r on ubuntu. have increased ram 4 gb 16 gb. sadly spending month on problem still error:

can not allocate vector of 600 mb 

i have gone through question https://stackoverflow.com/questions/1395229/increasing-or-decreasing-the-memory-available-to-r-processes has needed answer windows. process allocate 14 gb of memory rstudio on ubuntu.

sessioninfo() r version 3.3.1 (2016-06-21) platform: x86_64-pc-linux-gnu (64-bit) running under: ubuntu 14.04.5 lts locale:  [1] lc_ctype=en_us.utf-8       lc_numeric=c               lc_time=en_us.utf-8         [4] lc_collate=en_us.utf-8     lc_monetary=en_us.utf-8    lc_messages=en_us.utf-8     [7] lc_paper=en_us.utf-8       lc_name=c                  lc_address=c               [10] lc_telephone=c             lc_measurement=en_us.utf-8 lc_identification=c         attached base packages: [1] stats     graphics  grdevices utils     datasets  methods   base       loaded via namespace (and not attached): [1] tools_3.3.1