appendToFile.sh

#!/bin/bash
[ -t 0 ] && echo "stdin File Content is empty" && exit
IFS='' read -d '' -r CONTENT
[ -z "$1" ] && echo "FILENAME is empty" && exit
FILENAME=$1
PATH_FILE="${FILENAME}"
( [ -e "${PATH_FILE}" ] || touch "${PATH_FILE}" ) && [ ! -w "${PATH_FILE}" ] && echo "CONTENT can not be written to FILE: ${PATH_FILE}" && exit
#echo "${CONTENT}"
#echo "${PATH_FILE}"
echo -n "${CONTENT}" >> "${PATH_FILE}"