The leftmost six columns of the editor screen are referred to as the prefix area. The prefix area can contain the following:
A 6-digit line number (for example, 000010) for a line
that contains source code.
Note:
For technical reasons six digits are shown, but only four digits are
processed internally.
A series of apostrophes ('''''') for a blank source line.
It appears when the insert mode is active. Once you enter text in this line and
press ENTER, the apostrophes are replaced by a line number.
A series of asterisks (******) for an empty editing area.
You then need to activate the insert mode to enter text by using one of the
I (insert) line commands described in the relevant
section.
Text that indicates the contents or state of a line. For example:
=prof> indicates that this line contains information on
the current editor profile settings.
=cols> indicates that this line shows the current
column positions.
==chg> indicates that a character string was replaced
in this line.
.X indicates that this line is marked with a label.
To hide text in the prefix area and reset pending commands
In the command line, enter the following editor command:
RESET
In addition to showing the number of a source line or text, the prefix area is used for entering line commands as described in the relevant section.
You can protect the prefix area to avoid overwriting of source lines by
using the PROTECT editor
command described in Editor Commands.