Control Character
You create a control character by holding down the Control key while you strike another key. Control plus "A" generates Control-A. These are normally nonprinting characters, but they may do things to your terminal. For example, Control-G rings the bell. We assume that Control-Y is your interrupt character and that you do not use Control-D for end-of-file. Qedit uses control characters for a number of purposes:
In Modify, control characters specify the edit functions:
- Control-D for delete, Control-B for before, etc.
- Control-Y stops execution of the current Qedit command.
- Control-H causes the cursor to backspace one position in the current line.
- Control-I skips to the next tab position.
- Control-X cancels the current input line.
- Control-S pauses a listing that is printing too fast for you to read.
- Control-Q resumes a listing that you have paused with Control-S.
Editing control characters can be tricky. If you use Set Editinput to clean your text of line "noise", Qedit will not let you enter control characters in Add or Replace. If you use Modify, it treats all control characters as edit functions. If you use Visual, the block-mode terminal strips all control characters from the text. There are three things that you can do: 1) use Set Decimal ON and insert control characters using Change "$" '26, 2) use Set Editinput Data OFF and enter them using Display Functions in Add and Replace, and 3) use Set Mod Qzmod and insert them using Control-W, Control-P (put).