This document demonstrates how to create, list, execute, and remove aliases for commands running inside an instance.
Contents:
Create an alias
See also:
alias
To create an alias that runs a command on a given instance, use the command alias. The code below uses this command to create an alias lscc that will run the command ls inside an instance crazy-cat:
$ multipass alias crazy-cat:ls lscc
After running this command, the alias lscc is defined as running the command ls on the instance crazy-cat. If the alias name lscc is omitted, the alias name defaults to the name of the command to run (ls in this case).
Working directory mapping
By default, in case the host folder on which executing an alias is mounted on the instance, the working directory on the instance is changed to the mounted directory. This behavior can be avoided when defining the alias using the parameter --no-map-working-directory. For instance:
$ multipass alias crazy-cat:pwd pwdcc --no-map-working-directory
Alias contexts
See also:
prefer
Contexts are sets of aliases. While one can safely work with one context, named default, contexts can be useful in some scenarios. For instance, to define aliases with the same name in different instances. One can switch to using another context with multipass prefer secondary. Then, defining an alias in the new context is done in the usual way. The name of the alias can coincide with an already defined one. For example, multipass alias cozy-canary:ls lscc.
List defined aliases
See also:
aliases
To see the list of aliases defined so far, use the aliases command:
$ multipass aliases
Alias Instance Command Context Working directory
lscc crazy-cat ls default map
pwdcc crazy-cat pwd default default
lscc cozy-canary ls secondary* map
The current context is marked with an asterisk.
The column Working directory tells us on which directory of the host the alias will be executed. The value default means that the alias will be executed in the instance default working directory (normally, /home/ubuntu). The value map means that, in case the host directory from which the user calls the alias is mounted on the instance, the alias will be executed on the mounted directory on the instance. The value will be default only if the --no-map-working-directory argument is present at alias creation.
Execute an alias
There are three ways to execute the alias.
multipass <alias>
The first way of executing an alias is
$ multipass lscc
This shells into the instance cozy-canary, executes ls and returns to the host command-line, as if it was an exec command. Since two aliases have the same name, lscc, the executed one is the one on the current context.
In case of wanting to execute an alias outside the current context, a full-qualified alias name can be used.
multipass default.lscc
Arguments are also supported, provided you separate any options with --:
$ multipass lscc -- -l
or
$ multipass default.lscc -- -l
<alias>
The second way of running an alias is a two-step process:
Add Multipass alias script folder to system path
First, the Multipass alias script folder to the system path. The instructions to do so are displayed the first time one creates an alias, and vary for each platform. For instance,
$ multipass alias crazy-cat:ls lscc
You'll need to add this to your shell configuration (.bashrc, .zshrc or so) for
aliases to work without prefixing with `multipass`:
PATH="$PATH:/home/user/snap/multipass/common/bin"
Linux
Expand to see the instructions for Linux
In Linux, the shell configuration file must be modified. In most Linux distributions, the shell used by default is bash, which can be configured via the file .bashrc in the users home directory. Any text editor can be used for this, for example doing
$ nano ~/.bashrc
Once editing the file, the path can be modified by appending at its end a line such as
export PATH="$PATH:/home/user/snap/multipass/common/bin"
(remember to replace the correct folder by the one given in the output of the Multipass command above and to restart the shell).
In case of using zsh as shell, the file to modify is .zshrc instead of .bashrc; the procedure is the same.
MacOS
Expand to see the instructions for MacOS
In MacOS, the most commonly used shell is zsh. The procedure for adding a folder to the system path is the same as in Linux, described above.
Windows
Expand to see the instructions for Windows
For Windows, however, it is a bit more involved. To make the change permanent, use PowerShell to store the old system path, add the alias folder to it, and store the new path.
$old_path = (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH).path
$new_path = â$old_path;C:\Users\<user>\AppData\Local\Multipass\binâ
Set-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment' -Name PATH -Value $new_path
Donât forget to restart your terminal. The folder is now permanently added to your path, Multipass can now execute aliases just invoking their name.
Execute the alias
Once youâve added the alias folder to the system path, you can execute it directly (without mentioning multipass) as below:
$ lscc
or
$ default.lscc
This command (given that the path was already added to the systemâs path) is equivalent to multipass lscc. Arguments are also supported, without the need for --:
$ lscc -l
Remove an alias
See also:
unalias
Finally, to remove the alias lscc, issue:
$ multipass unalias lscc
or
$ multipass unalias default.lscc
The unalias command accepts many arguments, specifying more than one alias to remove. For example, removing at once aliases lscc and pwdcc is accomplished with:
$ multipass unalias lscc pwdcc
There is also the --all argument, aimed to remove all the defined aliases in the current context at once. Its usage is:
$ multipass unalias --all
An alias is also removed when the instance for which it was defined is purged. This means that multipass delete crazy-cat --purge will also remove the aliases lscc and pwdcc.
