| Now that you have completed this
chapter, you should have a firm understanding of the following:
The UNIX shell is a key component of
the UNIX operating system. The shell is the interface between the user
and the kernel. There are 3 commonly used shells: The Bourne shell,
the Korn shell, and the C shell. This chapter focused on the Korn and
C shells, which have more features than the Bourne and are the most
popular for regular users.
The default prompt for the Korn shell
is the dollar sign $ (same as Bourne shell). The default prompt
for the C shell is the percent sign %. Both the Korn and C shell users
can customize their prompts. The Korn shell sets the PS1 variable
and the C shell uses the set
prompt command.
Both Korn and C shells support aliasing
and history, although their command syntax varies somewhat. Aliases
allow the user to create new command names and associate them with
existing commands to increase productivity. The
history
command allows the user to
re-use previous commands to avoid having to type them in again.
The Korn shell provides command line
editing by allowing the user to use vi editor commands to modify
previous command lines. The C shell allows the user to make command
line substitutions for simple changes but does not have a command line
editing feature like the Korn shell.
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