#!/bin/bash
shopt -s expand_aliases
########################################################################################################################
###                                                                                                                    #
### Script:   R [--default-packages=pkg1,pgk2] [options] [< infile] [> outfile]                                        #
###                                                                                                                    #
### Purpose:  Start R in $HOME, using --quiet --save if no args and providing special arg --default-packages           #
###                                                                                                                    #
### Args:     --default-packages is a comma-separated list of packages to load (NULL for package:base only)            #
###           See R documentation for other options                                                                    #
###                                                                                                                    #
### Notes:    If no args, use --quiet --save                                                                           #
###           If any args, interpret --default-packages and let user decide if --quiet --save is appropriate           #
###           This means that if args but not --default-packages, this script is exactly like original R, except the   #
###           initial working directory is always $HOME                                                                #
###                                                                                                                    #
### Requires: R                                                                                                        #
###                                                                                                                    #
### Returns:  Starts R                                                                                                 #
###                                                                                                                    #
########################################################################################################################

cd  # start in $HOME
export TZ=UTC

# (1) no args, (2) --default-packages, (3) other
if [[ -z $* ]]; then
  args="--quiet --save"
elif [[ "$*" =~ --default-packages ]]; then
  pkg_arg=`expr "$*" : '.*\(--default-packages=[^ ]*\)'`
  pkg="${pkg_arg/--default-packages=/}"
  export R_DEFAULT_PACKAGES=$pkg
  args=${*/--default-packages=[^ ]*/}  # must not be quoted...
else
  args="$*"
fi

`which -a R | tail -1` $args