GNU ed reference manual - Line addressing Go to the first , previous , next , last section, table of contents .
Line addressing An address represents the number of a line in the buffer.
When a file is first read, the current address is set to the last line of the file. In general, the current address is set to the last line affected by a command. A line address is constructed from one of the bases in the list below, optionally followed by a numeric offset. Addresses are read from left to right, and their values are computed relative to the current address. An address range is two addresses separated either by a comma or semicolon.