One can use the search and replace command of "sed" also in vi editor. In the command, press ":" to open the command at the bottom of the windows and enter the following string to try it out on a file like "RollList.csv".
:%s/^\(.*\),\(.*\)$/\2,\[email protected]/g
The "%" at the beginning tells that search/replace command should be applied to the whole file. If we wish to apply to first 10 lines, we would write as follows:
:1,10s/^\(.*\),\(.*\)$/\2,\[email protected]/g
The "g" at the end tells that search/replace command should be applied to the lines as many times as possible. If we wish to apply only once, we would write as follows:
:%s/^\(.*\),\(.*\)$/\2,\[email protected]/