I am referring one basic pig script to count number of words as follows: A = load 'Desktop/wordcount.txt' as (col1:chararray); B = foreach A generate flatten(TOKENIZE(col1)) as word; grouped = group B by word; cnt = foreach grouped generate B, COUNT(B); dump cnt; And using wordcount.txt file with contents as below: This is pig test This is pig test word in the above code is used as an alias for foreach A generate flatten(TOKENIZE(col1)) . Not able to exactly understand the use of below line grouped = group B by word and the role of alias over here. ... View more