Determining line numbers

In these instructions, we made use of line numbers to refer to lines. How do you know what number a line has? If you just want to know the number of one line, move the cursor to that line and type

:.=

For another approach, type:

:set number

and press <Enter>. As you can see, this displays the number of every line in the file. If you want to turn off the display of line numbers, type:

:set nonumber

A number of special symbols can be used when specifying a range of lines. The . (period) stands for the line where the cursor is currently positioned. For example, move the cursor to this line and type:

:1,.s/$/???/

This adds ??? to the end of every line from the start of the file to the line containing the cursor.

When you issue a substitute command with a range, it is all right if some of the lines in the range do not contain the pattern you are replacing. When specifying a range of lines, $ stands for the last line in the file. For example, the command:

:1,$s/the/THE/g

changes every the in the file to uppercase (including words like there, where the is part of another word).