Nth Line

	Single Line
	1	Get the 4th line of a file. 2000.09.29
	From Nth to Mth Lines
	1	Get the 3rd through 6th lines of a file. 2000.09.29
	2	Delete the 3rd through 6th lines of a file. 2000.09.29

	3	Get the last 6 lines of a file. 2006.07.14
	4	Delete the last 6 lines of a file. 2000.09.29
	From the Last Nth to the Last Mth Lines
	1	Delete the LAST N-th line through the LAST M-th line of a datafile, where N is greater than M. 2012.01.05
	Every Nth Line of a File
	1	Get every Nth line of a file. 2009.05.15
	2	Append a line after every Nth (for example, 4th) line. 2001.02.22
	3	Delete every 4th line (e.g., 4th, 8th, 12th, ...) of a file. 2006.02.22
	Every N Lines of a File
	1	Join every N lines to one. 2009.09.15
	Every Line
	1	For each line of a file, append the previous line to the end of it. 2004.10.14
	2	For each line of a file, append the next line to the end of it. 2005.01.28