How to add a data column in existing file

Hi All

I need to add a column on my existing data file. I know similar posts are there but none of them were meeting my requirement. My input is

1.20 3.44 4.88
5.11 4.99 3.22
1.89 3.89 2.90

Desired output

1 1.20 3.44 4.88
2 5.11 4.99 3.22
3 1.89 3.89 2.90

I will highly appreciate your cordial help.

Thank you.

You can "cheat" by putting two columns in one.

awk '{ $1=NR" "$1 } 1' filename
1 Like

Thanks Corona, that works fine...