Write a SED script to add a new column in the beginning with entry "S1" or "S2". "S1" occurs periodically every 3rd line starting from first line, while rest is "S2"
Sample Input
Ajay,Chennai,Sales,40
Mona,Mumbai,Sales,60
Rajan,Patna,Buisness,50
Narayanan,Kochi,Sales,30
Anuj,Pune,Sales,70
Mohan,Jaipur,Buisness,70
Naga,Vizag,Sales,45
Chaitrali,Nagpur,Sales,90
Sanjana,Delhi,Buisness,80
Maitreyi,Bhopal,Sales,30
Sreni,Bangaluru,Sales,20
Sample Output
S1,Ajay,Chennai,Sales,40
S2,Mona,Mumbai,Sales,60
S2,Rajan,Patna,Buisness,50
S1,Narayanan,Kochi,Sales,30
S2,Anuj,Pune,Sales,70
S2,Mohan,Jaipur,Buisness,70
S1,Naga,Vizag,Sales,45
S2,Chaitrali,Nagpur,Sales,90
S2,Sanjana,Delhi,Buisness,80
S1,Maitreyi,Bhopal,Sales,30
S2,Sreni,Bangaluru,Sales,20
Write a SED script to add a new column in the beginning with entry "S1" or "S2". "S1" occurs periodically every 3rd line starting from first line, while rest is "S2" **Sample Input** ```bash Ajay,Chennai,Sales,40 Mona,Mumbai,Sales,60 Rajan,Patna,Buisness,50 Narayanan,Kochi,Sales,30 Anuj,Pune,Sales,70 Mohan,Jaipur,Buisness,70 Naga,Vizag,Sales,45 Chaitrali,Nagpur,Sales,90 Sanjana,Delhi,Buisness,80 Maitreyi,Bhopal,Sales,30 Sreni,Bangaluru,Sales,20 ``` **Sample Output** ```bash S1,Ajay,Chennai,Sales,40 S2,Mona,Mumbai,Sales,60 S2,Rajan,Patna,Buisness,50 S1,Narayanan,Kochi,Sales,30 S2,Anuj,Pune,Sales,70 S2,Mohan,Jaipur,Buisness,70 S1,Naga,Vizag,Sales,45 S2,Chaitrali,Nagpur,Sales,90 S2,Sanjana,Delhi,Buisness,80 S1,Maitreyi,Bhopal,Sales,30 S2,Sreni,Bangaluru,Sales,20 ``` Write a bash script to add serial number as first column to the CSV file `data.csv` and do a in-place replacement (overwrite) the file `data.csv`. The serial number starts with 1 on the first line. Write a SED script to mask the first 6 digits of the phone numbers with asterisks, such that only last four digits of phone number of ten digits are visible.