R function to read variable definition from a bash script

readSetting.R

readSetting <- function(setting_name, file){
        # Settings appear in the file in the form of
        #       SETTING_NAME="SETTING_VALUE"
        # with no leading whitespace characters.
        setting_begin <- paste0("^", setting_name, "=\"")
        setting_end <- "\" *$"
        setting_line <- grep(setting_begin, readLines(file), value=TRUE)
        setting_value <- gsub(setting_end, "", gsub(setting_begin, "", setting_line, fixed=FALSE), fixed=FALSE)
        return(setting_value)
}

settings_file <- "hpc_experiment_conf"
FUDGE_WORK_DIR <- readSetting("FUDGE_WORK_DIR",settings_file)
FUDGE_DATA_DIR <- readSetting("FUDGE_DATA_DIR",settings_file)
WALLTIME_COMBINE <- readSetting("WALLTIME_COMBINE",settings_file)
QUEUE_COMBINE <- readSetting("QUEUE_COMBINE",settings_file)
EMAIL_NOTIFY_COMBINE <- readSetting("EMAIL_NOTIFY_COMBINE",settings_file)


cat("FUDGE_WORK_DIR: ",FUDGE_WORK_DIR,"\n",sep="")
cat("FUDGE_DATA_DIR: ",FUDGE_DATA_DIR,"\n",sep="")
cat("WALLTIME_COMBINE: ",WALLTIME_COMBINE,"\n",sep="")
cat("QUEUE_COMBINE: ",QUEUE_COMBINE,"\n",sep="")
cat("EMAIL_NOTIFY_COMBINE: ",EMAIL_NOTIFY_COMBINE,"\n",sep="")