Migration from Bash/Zsh

Hash can load your existing shell configuration with a compatibility layer, making it easy to switch without losing your customizations.

Automatic Migration (First Run)

When you first launch Hash, it detects your previous shell and offers to load compatible settings:

Choosing "Yes" sources your existing config with a compatibility layer. Aliases, environment variables, and functions work automatically. Zsh-specific features are silently skipped.

Manual Migration

You can run migration manually at any time:

Checking Migration Status

See what was imported and what was skipped:

Load vs Generate

Hash offers two approaches for using your existing shell config:

Load (default)

When you run hash migrate and choose "Yes", Hash records your config files and sources them directly at startup with compatibility filtering:

Advantages:

• Changes to your .zshrc are automatically picked up
• You can keep using the same config for both shells during transition
• Zsh-specific commands are silently skipped at runtime
• Full bash syntax support including [[, ==, process substitution

Generate (standalone copy)

If you want a completely independent Hash config that doesn't depend on your old shell:

This extracts all compatible settings into a standalone ~/.hashrc file, with zsh-specific lines removed entirely.

Advantages:

• Clean break from your old shell config
• Faster startup (no compatibility filtering needed)
• Can safely delete or modify your .zshrc

What Gets Imported

Note: Aliases are converted to functions

Hash converts alias definitions to shell functions internally. This ensures that complex aliases with bash syntax (like && or ||) work correctly:

This is transparent — you use the alias name normally, and it works as expected. The conversion happens because Hash parses each command independently, so traditional alias expansion isn't available. Functions provide the same functionality with full bash syntax support.

What Gets Skipped

Troubleshooting

Tool-specific workarounds

Some popular tools need Hash-specific setup:

direnv:

zoxide:

starship:

Hash has built-in Starship support. Set prompt.mode = "starship" in your config.toml instead of using eval.

Bash Syntax Support

Hash fully supports bash 5.x syntax, including features that are shared between bash and zsh:

• [[ ... ]] extended test construct
• == string comparison (inside [[ ]])
• =~ regex matching
• Process substitution: <(cmd) and >(cmd)
• Arrays and associative arrays
• source and eval commands work with bash syntax

This means your existing bash and zsh configs will work without modification. The compatibility layer handles shell-specific features automatically.

Parse errors

If you see parse errors from your rc file, it may contain syntax that's specific to zsh and not shared with bash. Run hash migrate status to see what was skipped, or use hash migrate generate to create a clean config.