How to derive current date and time and append at the end of each line that contains 'Hello'

Question

I have the following file party.txt that contains something like the following:

Hello Jacky
Hello Peter
Bye Johnson
Hello Willy
Bye Johnny
Hello Mar         


        

Answer 1

using posix sed (and a sub shell due to missing time function in sed)

sed -n "/^Hello/ s/$/ $( date +'%Y-%m-%d' )/p" party.txt

return

Hello Jacky 2016-11-10
Hello Peter 2016-11-10
Hello Willy 2016-11-10
Hello Mary 2016-11-10
Hello Wendy 2016-11-10