Working with the Linux Command Prompt
Linux commands share a simple, common structure. This section describes their common structure and explains how you can obtain helpful information about the commands available to you.
Commands and Arguments
The general form of a shell command line is this:
The command determines what operation the shell
will perform and the
arguments—which, as indicated by the
enclosing brackets, may or may not appear—customize, or
fine-tune, the operation. Sometimes the command
specifies a program file that will be launched and run;
such a command is called an external command.
Linux generally stores these files in
/usr/local/bin. System administration commands
are generally stored in
/usr/sbin, which are included by default in the
path of the root user. When a command specifies a program file, the
shell passes any specified arguments to the program, which scans and
interprets them, adjusting its operation accordingly.
However, some commands are not
program files; instead they are built-in commands interpreted by the
shell itself. One important way in which shells differ is in the
built-in commands that they support. Later in this section,
you’ll learn about some of
The name of a Linux command almost always consists of lowercase letters and digits. Most commands let you specify options or arguments. However, in any given case, you may not need to do so. ...