### 1.4 Conventions used in this manual ¶

This manual contains many examples which can be typed at the keyboard. A command entered at the terminal is shown like this,

    $ command

followed by its output. For example:

    $ echo "hello world"
    hello world

The first character on the line is the terminal prompt, and should not be typed. The dollar sign ‘`$`’ is used as the standard prompt in this manual, although some systems may use a different character.

When a command in an example is too long to fit in a single line it is wrapped and then indented on subsequent lines, like this:

    $ echo "an example of a line which is too long to fit
        in this manual"

When entered at the keyboard, the entire command should be typed on a single line.

The example source files used in this manual can be downloaded from the publisher’s website,2 or entered by hand using any text editor, such as the standard GNU editor, `emacs`. The example compilation commands use `gcc` and `g++` as the names of the GNU C and C++ compilers, and `cc` to refer to other compilers. The example programs should work with any version of GCC. Any command-line options which are only available in recent versions of GCC are noted in the text.

The examples assume the use of a GNU operating system—there may be minor differences in the output on other systems. Some non-essential and verbose system-dependent output messages (such as very long system paths) have been edited in the examples for brevity. The commands for setting environment variables use the syntax of the standard GNU shell (`bash`), and should work with any version of the Bourne shell.

#### Footnotes

##### (2)

See http://www.network-theory.co.uk/gcc/intro/