Nushell alias converter

Why?

Nushell doesn’t directly support bash aliases due to syntax differences, making migration difficult since some aliases may break, and you can't source .bash_aliases directly.

nu-alias-converter automates converting aliases from files or directories to Nushell syntax for easy loading in your config. It validates aliases using the nu-parser crate to prevent config issues.

If you prefer keeping all your aliases in a single file (e.g., ~/.bash_aliases) for cross-shell compatibility, this tool is perfect for you.

Key features:

• Converts bash aliases to Nushell syntax
• Comments out invalid aliases with explanations
• Ignores aliases based on user-defined criteria
• Syncs aliases at each shell session start
• Allows manual review of problematic aliases

This project was built to learn Rust and tree-sitter parsing, but it also helps anyone who has accumulated aliases over the years to transition smoothly to Nushell while retaining compatibility.

Installation

cargo install nu-alias-converter

Usage

Convert a single file to Nushell aliases:

# will generate a bash-aliases.nu file in the same directory
nu-alias-converter .bash_aliases

Convert all files with aliases in a directory:

# will search for alias files in the specified directory and generate
# a bash-aliases.nu file in the same directory
nu-alias-converter /path/to/directory

For optimal use, integrate it into your Nushell environment. This approach offers two key advantages:

1. Automatic regeneration: The alias file is recreated at the start of each shell session.
2. Continuous synchronization: Your Nushell aliases stay up-to-date with your Bash aliases.

This ensures that any changes to your Bash aliases are immediately reflected in your Nushell environment.

Add this to the end of your env.nu file (find it by running $nu.env-path in Nushell):

# This command will be shorter in the future
nu-alias-converter ~/.bash_aliases -o $"($nu.default-config-dir)/bash-aliases.nu" | ignore

Now add this to your config.nu to source the generated aliases file (find the path with nu.config-path):

source bash_aliases.nu

This will make the bash aliases available in the Nushell environment.

Ignoring Aliases

Sometimes there are some aliases that you don't want to convert to Nushell, maybe because they are not valid or you don't want to use them in Nushell.

You can ignore aliases by adding them to a .aliasignore file in the root of your home directory or in the nushell config directory.

The file should contain all the aliases that should be ignored, one per line:

# ~/.aliasignore
ls
la
gst

This will not convert any of those aliases to nushell.

Another option is to ignore all the aliases that use a command, the syntax would be the same but with a bang (!) in front of the command name:

# ~/.aliasignore
la
gst
!ls
!htop

This will also ignore all the aliases that use ls and htop.

Shell support

Shell	Status	Aliases
sh	Supported	✓
bash	Supported	✓
zsh	Not tested	~
fish	Not supported	✗

• ✓ : Fully supported
• ~ : Should work but some limitations may apply
• ✗ : Not supported

How?

The CLI app will be written in Rust, needs to be to use the nushell crates used for parsing. It will use treesitter to parse the bash script and get all the aliases.

The aliases will then be converted to the nushell format using the nu-parser crate. After converting, the aliases will be validated, if an alias is not valid it will be generated as a comment with the information of the parsing error. So the user can check it and fix it manually. It would be nice to auto generate the rust code from the content of the alias is the parsing fails but this is not a priority for now.

The converted aliases are written to a file. You can either generate them manually or use the Nushell environment. If using the environment method, the file will regenerate at the start of each shell session.

Unnecessary diagram:
Not that complex but I always wanted to try this out.

---
config:
  theme: dark
  look: classic
  layout: dagre
---
graph TD
  A[CLI App in Rust] --> K[Read .aliasignore file]
  A --> B[Parse Bash with Tree-sitter]
  A --> N[Check for Directory]
  N -->|Is Directory| O[Search for Alias Files]
  O --> B
  N -->|Is File| B
  K --> L[Should ignore alias?]
  B --> L
  L -->|No| C[Convert to Nushell format]
  L -->|Yes| M[Skip alias]
  C --> D[Validate Alias Syntax]
  D --> E[Write Valid Aliases to Nushell File]
  E --> F[Manual Method]
  E --> G[Nushell Environment Method]
  G --> H[Regenerate File at Each Shell Session]
  D --> I[Comment Out Invalid Aliases]
  I --> J[Include Parsing Error Information]

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