1. Conventions used in this document

To make sure that what you understand is what I said, we're agreeing on using the following conventions in this document:

Table 1. Conventions

When I want to say... I use...
the user's prompt $
the superuser's prompt (root) #
a filename file
a directory's name some/directory
a command's name command parameter1 parameter2 ...
an optional parameter in a command command obligatory-parameter [optional-parameter]
the contents of a file
    type this at your file
pay attention to this
Warning

this is a warning

a comment on something

Note: this is a note

tips on how to do something or to improve your work

Tip: This is a tip ;-)

an argument which can be used in, e.g., two different ways use_this | or_this[a]
Notes:
a. The key thing here is the | sign.