Custom Sweave bash script

sweave.sh

#!/bin/bash

FILEBASE=${1%.*}
FILEXT=${1##*.}
FILEPATH=${1%/*}

TEXFILE=$FILEBASE.tex
PDFFILE=$FILEBASE.pdf

# errorexit

function errorexit () {
    echo "Error: $1"
    exit 1
}

# check if file exists
if [ ! -f $1 ]; then
    errorexit "File $1 not found!"
else
# check for filename length
    if [ ${#1} -lt 1 ]; then
    errorexit "Need to specify argument file!"
    else
    # if filelength OK, check extension
	if [ $FILEXT != "Rnw" ]; then
	    errorexit "You must pass Sweave (.Rnw) file!"
	    # finally, run Sweave
	else
	    cd $FILEPATH && R CMD Sweave $1
	    # latex $TEXFILE
	    pdflatex $TEXFILE
	    xdg-open $PDFFILE &
	fi
    fi
fi