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The R home directory

The R home directory contains the configuration and installation files. It is identified with the R_HOME environment variable.

Determine the path of the R home directory

In an R session, the value of R_HOME can be displayed like so:
> Sys.getenv('R_HOME')
[1] "/usr/lib/R"
Alternatively, it can be shown on a shell by executing:
$ R RHOME
/usr/lib/ R

Files found in the R home directory

etc/Renviron

R_HOME/etc/Renviron contains environment variables to configure some aspects of R.
This file is read early in the start-up processing.
In my current Debian installation (apt install r-base), /usr/lib/R/etc/Renviron is a symlink to /etc/R/Renviron.

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1743242211, '18.218.93.239', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/languages/R/home-directory(57): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78