Input and output: Overwrite/Append/Column Append

Overwrite: input.txt > P0(apple=>fruit) > P1 > output.txt

 

Append: input.txt > p0(add Header,time) >p1 >> output.txt

 

Append: input.txt >> P0 > P0

 

Column Append: input.txt > P0 >P1 >>> output.txt

 

Column Append: P0 >>> P1