4. Sed line number control

• sed -n ‘1d’ files

just delete the first line

• ‘2,5p’ 表示 prints all the lines from 2 to 5

• ($) which represents the last line of the file

• '2,+4 p' books.txt prints the next 4 lines from the second line

• ‘M~n’ 50~5 matches line number 50, 55, 60, 65, and so on.