Command Aliases

By Danny Kalev, ITworld |  How-to

The 'alias' command enables you to create another name for a command.
The alias doesn't replace the original command, though; it's simply a
synonym for it. You define an alias using the 'alias' command followed
by an equal sign and the command that the alias will stand for. For
example, the following command defines 'list' as an alias for 'ls':

$alias list=ls

You use this alias as you would use the original 'ls' command:

$list
mypog.c myprog.o

Command Options and Parameters
To include command options in an alias, enclose the command and its
option(s) in single quotes:

$alias sizes='ls -s'

The -s option lists files with their sizes in blocks. Therefore, the
alias 'sizes' displays the files in the current directory with their
sizes in blocks:

$sizes
mypog.c 6 myprog.o 12

You may include command parameters in an alias. The following alias
displays only files with the .c extension:

$alias listc='ls *.c'
$listc
mypog.c

You can use an exiting command name as an alias, too. In this case, the
alias hides the original command. Use this feature to hide dangerous
commands that might delete files inadvertently, change their names,
etc. Let's look at a concrete example. To ensure that 'mv' command
doesn't overwrite exiting files, define an alias called 'mv' that
overrides the 'mv -i' command (the -i option queries the user before
deleting existing files):

$alias mv='mv -i'

Listing and Canceling Existing Aliases
To list all the aliases in effect, use the 'alias' command without
additional parameters:

$alias
list = ls -s
sizes = ls -s
listc = ls *.c
rm = rm -i

To cancel an exiting alias, use the 'unalias' command followed by the
alias you wish to remove:

$unalias listc

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