Shell Programming and Scripting

awk -F, 'NR==1{print > "TATA34052016__testcase.csv"; print > "TATA79802016_testcase.csv"} ($NF ~ /TATA3405/){print >> "TATA34052016__testcase.csv"} ($NF ~ /TATA7980/){print >> "TATA79802016_testcase.csv"}'  Input_file

 for my $year (keys $data{$fname}) {

 for my $year (keys %{$data{$fname}}) {

awk '
NR==1   {HD = $0
         next
        }

!FN[$5] {FN[$5] = $5 "2016__testcase.csv"
         print HD  >  FN[$5]
        }

        {print $0  >  FN[$5]
        }
' FS="," file

awk '
NR==1   {HD = $0 # Get first line ie header
         next    # Dont run any other commands. ie read next line.
        }

!FN[$5] {FN[$5] = $5 "2016__testcase.csv" # here set array FN with index set as value of $5 . it is true twice for given input sample.
         print HD  >  FN[$5] # redirect header from HD to file
        }

        {print $0  >  FN[$5] # Print the current line to file. How this differentiates two different $5 , lines and print them to respective files ?
        }
' FS="," file