Shell Programming and Scripting

FILE_EXISTS=`ls ${INPUT_DIR}/*.txt | wc -l`
if [ $FILE_EXISTS -eq 0 ];
then
echo "No file found hence sleeping for 10 secs..."
sleep 10;
continue;
fi 

FILE_EXISTS=`ls ${INPUT_DIR}/*.txt >/dev/null 2>&1 | wc -l`
if [ $FILE_EXISTS -eq 0 ];
      then
      echo "No file found hence sleeping for 10 secs..."
      sleep 10;
      continue;
fi 

TRY=${INPUT_DIR}/*.txt
if [ "$TRY" = "${INPUT_DIR}/\*.txt" ]
then
    echo No files there!
fi

exists()
{ 
  [ -e "$1" ]
}

until exists "${INPUT_DIR}"/*.txt
do
  echo "No file found hence sleeping for 10 secs..."
  sleep 10
done