Summary Box
One of Unix's best
features is the shell's command line. Why? Nearly
every modern operating system has a command line; we
don't use card readers with obscure job setup cards
any more. What makes Unix's special?
The Unix
shell command line allows lots of shortcuts. Some of these
you'll find in other operating systems; some you
won't. In this chapter, we'll
introduce a lot of these shortcuts. Among other things,
we'll discuss:
-
How to run commands more than
once (Section 28.8).
-
Filename completion
(Section 28.6, Section 28.7), which allows you to type the beginning of a
filename and let the shell fill in the rest. (This is finally
possible on certain Redmond-born OSes as well, but it usually
involves a registry hack or two.)
-
Command substitution
(Section 28.14), which lets you use the output from one
command as arguments to another. (Note that this is
different from pipelining.)
-
Process substitution in
bash, and a script named ! for
other shells, lets you put the output of a command into a temporary
file and give that filename to a process.
-
The ability to repeat commands with various
methods (Section 28.10, Section 28.11).
-
Handling of command lines that become too
long (Section 28.17).
Some fundamental command-line features that we
aren't discussing in this chapter, but which are
discussed elsewhere, are:
You don't need to be a command-line virtuoso to use
Unix effectively. But you'd be surprised at how much
you can do with a few tricks. If all you can do at the command line
is type ls or start Mozilla or the Gimp,
you're missing out on a lot.
-- ML
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