title: Append\Union two or several tables into one
body: <p>I input 5 text data sets into R using <code>read.table</code>. 
  Each data set has the same structure (100 rows,  50 cols).
  I would like to union\append all the five tables together into one table, which will be 500 rows * 50 cols.
  Anyone know how to do that?</p>