nushell/docs/commands/alias.md

alias

This command allows you to define shortcuts for other common commands.

The command expects three parameters:

• the name of alias
• the parameters as a space-separated list ([a b ...]), can be empty ([])
• the body of the alias as a {...} block

Examples

Define a custom myecho command as an alias:

> alias myecho [msg] { echo $msg }
> myecho "hello world"
hello world

Since the parameters are well defined, calling the command with the wrong number of parameters will fail properly:

> myecho hello world
error: myecho unexpected world
- shell:1:18
1 | myecho hello world
  |              ^^^^^ unexpected argument (try myecho -h)

The suggested help command works!

> myecho -h

Usage:
  > myecho ($msg) {flags}

parameters:
  ($msg)

flags:
  -h, --help: Display this help message

Persistent aliases

Aliases are most useful when they are persistent. For that, add them to your startup config:

> config --set [startup ["alias myecho [msg] { echo $msg }"]]

This is fine for the first alias, but since it overwrites the startup config, you need a different approach for additional aliases.

To add a 2nd alias:

config --get startup | append "alias s [] { git status -sb }" | config --set_into startup

This first reads the startup config (a table of strings), then appends another alias, then sets the startup config with the output of the pipeline.

To make this process easier, you could define another alias:

> alias addalias [alias-string] { config --get startup | append $alias-string | config --set_into startup }

Then use that to add more aliases:

addalias "alias s [] { git status -sb }"