In the examples given in the other sections, a specific set of typgraphic conventions are used. We distinguish between user input and computer output using different fonts:
indicates text that you are supposed to type,
indicates text that the computer prints.
Material within angular brackets denote logical entities, e.g., <user> indicates that you should type your user-name. The shell's prompt is denoted with "$ ", so, e.g., the following indicates that you're supposed to type ls to the shell:
$ ls
Especially in the section about emacs key sequences are written with the convention that:
S- means hold down a shift key,
C- means hold down the control key,
M- means hold down the meta key. (This is the left windows key. On older keyboards without windows keys it is the left alt key).
A- means hold down the left alt key (note that on older keyboards this is the same as M-),
G- means hold down the ''AltGr'' key.
RET means the return key, and certain other named keys are written with their names.
So, e.g., C-x C-f means holding down the control key and pressing "x" followed by "f".