Introduction to Shell Aliases (Unix Power Tools, 3rd Edition)
29.2. Introduction to Shell Aliases
All
shells except the original Bourne shell have an
"alias" facility that lets you
define abbreviations for commands.
The simplest C shell
aliases, which are similar to the alias facility in newer
Bourne-type
shells, are simply a short name for a command and, often, command
options or arguments too. The C shell's aliases can
get very complicated. Section 29.3 describes
how a C shell alias can use arguments from its command line as
it's invoked.
As we've said, aliases in Bourne-type shells
(bash,
zsh, and ksh) are simpler.
Section 29.4 covers some of the differences
between those shells and the C shells. Still, the ideas for custom C
shell commands are useful in any kind of shell, and if you
can't write something in a simple Bourne-type alias,
you almost certainly can do it in a shell
function (Section 29.11).
You can define aliases from the command
line, for use in just your current shell. Any aliases you define can
also be placed in your shell setup
file (Section 3.3), so
they'll be available whenever
you're using your shell.
Note that aliases are not passed to subprocesses
(Section 3.3), so putting
them in a setup file that's read only by login
shells or top-level shells probably isn't what you
want. (One exception is an alias for a command that you want to run
only in a login shell. For instance, you could
define an alias named X that starts your X Window
System. If that alias isn't defined in subshells,
you'll get a message like X: command not
found if you try to start the window system from an
existing window.)
A common approach is to create separate files for each shell that
store your aliases (such as .bash_aliases for
bash or .aliases.csh for the
C shell), so that you may source them whenever you like.
Here's one last note that applies to all shells.
Anytime you want a list of the aliases currently set, just type
alias.
--JP, ML, DG, and SJC
29. Custom Commands29.3. C-Shell Aliases with Command-Line Arguments
Copyright © 2003 O'Reilly & Associates. All rights reserved.
Wyszukiwarka
Podobne podstrony:
ch29ch29 (5)ch29ch29ch29 (7)ch29ch29 (4)ch29ch29Ch29ch29ch29ch29 (2)ch29CH29CH29 (10)więcej podobnych podstron