Sed only prints modified rows

Sed only prints modified rows. We print qualified rows through grep or egrep (grep-E). To print row numbers, use the-n parameter. However, if we want to modify the text first and then print the modified rows, we can use sed to use the-n and p parameters. For example, 1sed-n's/main/mains/'P test.txt first uses-n to stop the output of the modified text. Use p to print the modified rows. Perl also has the grep command, which returns values and is an array. Example: 1my @ array = qw (greyhound bloodhound hello hand); 2my @ hounds = grep s/hound/hounds/, @ array; # The returned value is an array. If it is a constant, the number of elements in the array. 3 print "hounds: @ hounds \ n ";