R sys env

> Sys.getenv()
__CF_USER_TEXT_ENCODING
                        0x1F5:0x0:0x0
Apple_PubSub_Socket_Render
                        /private/tmp/com.apple.launchd.sb8F8VC6qn/Render
DISPLAY                 :0
DYLD_FALLBACK_LIBRARY_PATH
                        /Library/Frameworks/R.framework/Resources/lib:/Users/username/lib:/usr/local/lib:/usr/lib::
EDITOR                  vi
GIT_ASKPASS             rpostback-askpass
HOME                    /Users/username
LANG                    en_GB.UTF-8
LC_CTYPE                en_GB.UTF-8
LN_S                    ln -s
LOGNAME                 username
MAKE                    make
PAGER                   /usr/bin/less
PATH                    /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
R_BROWSER               /usr/bin/open
R_BZIPCMD               /usr/bin/bzip2
R_DOC_DIR               /Library/Frameworks/R.framework/Resources/doc
R_GZIPCMD               /usr/bin/gzip
R_HOME                  /Library/Frameworks/R.framework/Resources
R_INCLUDE_DIR           /Library/Frameworks/R.framework/Resources/include
R_LIBS_SITE
R_LIBS_USER             ~/Library/R/3.2/library
R_PAPERSIZE             a4
R_PDFVIEWER             /usr/bin/open
R_PLATFORM              x86_64-apple-darwin13.4.0
R_PRINTCMD              lpr
R_QPDF                  /Library/Frameworks/R.framework/Resources/bin/qpdf
R_RD4PDF                times,inconsolata,hyper
R_SESSION_TMPDIR        /var/folders/57/w1dxjlfx4b9bsbpjg_98pvb80000gn/T//RtmpCKuA7Q
R_SHARE_DIR             /Library/Frameworks/R.framework/Resources/share
R_SYSTEM_ABI            osx,gcc,gxx,gfortran,?
R_TEXI2DVICMD           /usr/local/bin/texi2dvi
R_UNZIPCMD              /usr/bin/unzip
R_ZIPCMD                /usr/bin/zip
RMARKDOWN_MATHJAX_PATH
                        /Applications/RStudio.app/Contents/Resources/resources/mathjax-23
RS_RPOSTBACK_PATH       /Applications/RStudio.app/Contents/MacOS/rpostback
RS_SHARED_SECRET        278ed779-04df-49c0-bfe1-a1d073f637b9
RSTUDIO                 1
RSTUDIO_PANDOC          /Applications/RStudio.app/Contents/MacOS/pandoc
RSTUDIO_SESSION_PORT    29860
RSTUDIO_USER_IDENTITY   username
SED                     /usr/bin/sed
SHELL                   /bin/bash
SSH_AUTH_SOCK           /private/tmp/com.apple.launchd.GvEmCeD0yr/Listeners
TAR                     /usr/bin/tar
TMPDIR                  /var/folders/57/w1dxjlfx4b9bsbpjg_98pvb80000gn/T/
USER                    username
XPC_FLAGS               0x0
XPC_SERVICE_NAME        0