Line tagging is sufficient for most editing tasks. It falls short in those cases where you wish to operate on a block of text within a line. This occurs most frequently in the preparation of multi-column text. For example, if you wished to move the block of "C"s
AAAAAAA BBBBBBB CCCCCCC AAAAAAA BBBBBBB CCCCCCC AAAAAAA BBBBBBB CCCCCCC AAAAAAA BBBBBBB CCCCCCC DDDDDDD DDDDDDD DDDDDDD DDDDDDD
under the block of "B"s you would need to tag only the "C"s, not the "A"s and "B"s. Enter the text above and position yourself on the first character of the first line of "C"s. Depress the F7 (tag key) twice in rapid succession. The first depression will tag the line and the second depression will turn on the block tag feature and set a left limit at your cursor. The characters from the first C to the end of your line will be displayed in inverse video.
Now move your cursor to the C in the lower right corner and depress the F7 key again. You need only depress it once. This will tag the last line of "C"s and set a right limit. The block of "C"s should now be displayed in inverse video. If you wish, you may adjust the line range being tagged or the limits of the tag by moving your cursor and typing the F7 key. Unlike line tagging, typing F7 again will not remove a block tag.
Now move your cursor under the first B on the line containing the first row of "D"s and depress the F8 key. You will be queried with a more extensive list of operations then a simple line delete. They are