UNIX for Dummies Questions & Answers

Now before this thread gets closed, please be aware this is not classwork or homework, I am trying to learn unix by myself, and have come stuck below. So it is a pointless to close this thread, as I am trying to improve my unix by asking advice from people. That is what I assume a forum is for!

I am trying to work out how to complete this question, and after learning a bit more unix. i have written an answer to it. Can anyone check to see if it is correct and what improvements need to be made?

Write a pipeline that updates the content of a file (a file of your choice) by replacing all matches of the word ‘and' with the symbol ‘&' and by replacing the end of each line with the user login name. If the command completes successfully it should print ‘YES', otherwise it should print ‘NO'.

cat text.txt | sed -e s/and/$USER/g -e s/$/”&”/g | cat -> text.txt
&& echo yes || echo no

thanks
vish

Thread closed. The question was asked two years ago on another forum.