whi

whi is a smarter which that also lets you rearrange your current shell's PATH safely. Install the shell integration once, run the high level commands (prefer, add, move, switch, clean, delete, undo, redo, reset, diff, apply, save, load, list, rmp, file, source, exit, var, shorthands), and grab the helper shortcuts if you like terse aliases.

Heads up: mutation commands only run after the integration exports WHI_SHELL_INITIALIZED=1. If you see the integration warning, run the snippet for your shell and add it to your config for persistence.

Install & Integrate

cargo install whi

Pick the snippet for your shell and paste it into a terminal. Add the same line to the END of your shell config so it runs on startup after all PATH modifications.

# Bash
eval "$(whi init bash)"      # add to the END of ~/.bashrc (or the file you source)

# Zsh
eval "$(whi init zsh)"       # add to the END of ~/.zshrc

# Fish
whi init fish | source        # add to the END of ~/.config/fish/config.fish

Important: The integration must be at the END of your config so whi captures your final PATH after all modifications (homebrew, cargo, etc.).

The snippet:

• Loads any previously saved PATH (from ~/.whi/saved_path_*)
• Defines helper functions (whip, whiad, whia, whim, whis, whiu, whir, whil, whiv, whish, etc.)
• Exports WHI_SHELL_INITIALIZED=1 so whi knows it's safe to mutate PATH
• Captures the final PATH as your session baseline for undo/diff tracking

Core Commands

All of these operate on the current shell session. Each command prints the updated PATH; the integration captures the string and updates PATH for you.

Querying executables

whi cargo                    # show the first match (with PATH index)
whi -n cargo                 # no index, same output which gives
whi -a cargo                 # show all matches
# Shorthand: whia
whi -an cargo                # all matches, no index

# Fuzzy search fallback (if exact match fails)
whi carg                     # finds "cargo" via fuzzy matching

# Show full path (line separated)
whi -f                       # list all PATH entries
whi -fn                      # list all PATH entries, no index

# This is cool ... list all matches, newline, list full path
# with all path entries containing the binary highlighted
whi --full cargo

Useful flags:

• -a/--all
• -f/--full
• -l/--follow-symlinks
• -s/--stat
• -0/--print0
• -q/--quiet
• --silent
• --color <auto|never|always>
• --path <PATH>

PATH manipulation

# Add paths to PATH (prepends by default)
whi add ~/.local/bin                 # add single path
whi add ~/bin ~/.cargo/bin           # add multiple paths
# Shorthand: whiad

# Prefer: make an executable win (or add a path)
# The Swiss Army knife - works with index, path, or fuzzy pattern
# Makes minimal changes to achieve the goal

whi prefer cargo 5                   # prefer by index
whi prefer cargo ~/.cargo/bin        # prefer by exact path (moves if present)
whi prefer cargo ~/new/rust/bin      # adds path if not in PATH (validates cargo exists!)
whi prefer cargo toolchain stable    # prefer by fuzzy pattern
whi prefer bat github release        # another fuzzy example
whi prefer ~/.local/bin              # no executable -> add path (like fish_add_path)

# Move and swap entries by index (1-based)
whi move 12 1
whi switch 4 9

# Clean duplicates
whi clean

# Delete entries
whi delete 3 9               # specific indices
whi delete ~/.local/bin      # exact path
whi delete build temp        # fuzzy - all paths matching pattern

History & state management

# Undo/redo/reset PATH changes
whi undo                     # undo last operation
whi undo 3                   # undo last 3 operations
whi redo                     # redo next operation
whi redo 2                   # redo next 2 operations
whi reset                    # reset to initial session state

# Inspect PATH changes
whi diff                     # show changes since session start
whi diff full                # show all entries (including unchanged)

Persistence & profiles

# Persist PATH to shell config files
whi apply                    # save to current shell's config
whi apply fish               # save to specific shell
whi apply all                # save to all shells (bash/zsh/fish)
whi apply --force [--no-protect]   # required when running inside an active whi venv

# Profile management
whi save work                # save current PATH as profile "work"
whi load work                # load profile "work"
whi list                     # list all saved profiles
whi rmp work                 # remove profile "work"

Environment variables

# Query environment variables
whi var PATH                 # show PATH variable (exact match, case-insensitive)
whi var cargo                # fuzzy search for variables matching 'cargo'
whi var -f                   # list all environment variables (sorted)
# Shorthand: whiv

# Show all available shortcuts
whi shorthands               # display table of all whi* shorthands
# Shorthand: whish

Virtual environments (venv)

whi can create project-specific PATH environments similar to Python virtualenvs or direnv, but for PATH management. This is perfect for projects that need specific tool versions or custom PATH configurations.

# Create whifile from current PATH (like requirements.txt for PATH)
whi file                     # create whifile in current directory
whi file -f                  # force overwrite existing whifile

# Activate venv (read whifile and switch PATH)
whi source                   # activate venv from ./whifile
# Shell shows: [dirname] user@host:~/project $

# Exit venv (restore previous PATH)
whi exit                     # deactivate and restore PATH

How it works:

• whi file snapshots your current PATH into a whifile in the current directory
• whi source reads whifile and replaces your PATH (saves old PATH for restore)
• whi exit restores your previous PATH
• Your shell prompt shows [venv-name] when active (like Python venvs)
• All PATH operations (prefer, move, delete, etc.) work normally inside venvs
• Venv state is session-specific (different terminals = different venv states)

Use cases:

• Lock tool versions per project (e.g., specific Node, Python, Ruby versions)
• Isolate project-specific binaries from global PATH
• Test PATH configurations before applying globally
• Share reproducible development environments via version control

Auto-activation: You can enable auto-activation in ~/.whi/config.toml:

[venv]
auto_activate_file = true   # automatically source whifile when entering directories
auto_deactivate_file = true # automatically run whi exit (and extra exit hooks) when leaving

When enabled, the shell integration will automatically activate venvs when you cd into directories containing whifile and automatically run whi exit (including $source … <exit_command> hooks and $pyenv deactivation) when you leave.

Known Issue: Auto-activation currently does not work in Zsh. Bash and Fish work correctly. For Zsh users, please manually run whi source when entering directories with a whifile. This will be fixed in a future release.

whifile format (v2 / 0.6.0+): The file uses a directive-based format with multiple PATH and ENV strategies:

# Replace session PATH entirely
!path.replace
/usr/local/bin
/usr/bin
/bin
~/custom/bin
/Users/$USER/.local/bin

# Or prepend to session PATH
# !path.prepend
# ~/my-tools/bin

# Or append to session PATH
# !path.append
# ~/extra/bin

# Set environment variables
!env.set
# Comments are supported
RUST_LOG debug
PROJECT_ROOT $(pwd)
CONFIG_DIR $HOME/.config/myapp
MY_VAR hello world

# Or replace all env vars (whitelist mode)
# !env.replace
# KEEP_THIS value
# AND_THIS value

# Or unset specific vars
# !env.unset
# REMOVE_THIS
# AND_THIS

PATH directives (mutually exclusive):

• !path.replace - Replace session PATH entirely with listed paths
• !path.prepend - Prepend paths to session PATH
• !path.append - Append paths to session PATH
• Each path is on its own line
• Supports shell variable expansion: $VAR, ${VAR}, ~, $(command)
• Variables are expanded when sourcing the venv

ENV directives:

• !env.set - Set specific environment variables (default)
• !env.replace - Replace all env vars (whitelist mode, auto-unsets others)
• !env.unset - Unset specific variables
• Fish-style syntax: KEY value (space-separated, no = or quotes needed)
• Supports shell variable expansion: $VAR, ${VAR}, ~, $(command), `command`
• Values can contain spaces, special characters (:, =, /, etc.)
• Comments start with #
• Variables are set when entering venv, unset when exiting

Extra directives (optional):

• !whi.extra - Source scripts or activate Python virtual environments
• Executed AFTER !path and !env sections to prevent interference
• Two directive types:
  • $source /path/to/script – Source any shell script (user's responsibility for shell compatibility). Append an optional exit command to run during whi exit: $source /path/to/script cleanup_command --flag. The exit command runs before Whi unsets venv variables so you can undo whatever the script configured.
  • $pyenv /path/to/venv – Activate Python venv (auto-detects shell and sources activate/activate.fish). Whi keeps a guard around the virtualenv so calling deactivate directly prints environment managed by whi...; use whi exit (or auto-deactivate) so Whi can restore history and PATH correctly. Regular $source directives do not install this guard.
• Supports shell variable expansion: $VAR, ${VAR}, ~, $(command)
• Python venv example: $pyenv $(pwd)/.venv or $pyenv .venv (both work)
• On whi exit, runs deactivate for Python venvs automatically and executes any $source … <exit_command> hooks you defined
• With [venv] auto_activate_file/auto_deactivate_file enabled in config.toml, the shell integration automatically applies $pyenv/$source directives (and their exit commands) when you cd into or out of a whifile directory.

Example:

!whi.extra
$pyenv $(pwd)/.venv
$source ~/.config/project-setup.sh

Legacy format support: Files with PATH! and ENV! sections (pre-0.6.0) are automatically converted to !path.replace and !env.set for backward compatibility.

Shell prompt behaviour

Whi uses virtualenv's standard environment variables (VIRTUAL_ENV and VIRTUAL_ENV_PROMPT) for venv indication. Modern prompt frameworks (Starship, oh-my-posh, Tide, powerlevel10k, etc.) automatically detect these variables and display the venv indicator in their own style - no manual configuration needed!

whi --help shows the verbs (prefer, add, move, switch, clean, delete, undo, redo, reset, diff, apply, save, load, list, rmp, file, source, exit, var, shorthands). The integration intercepts those public names and rewrites them to the hidden __… subcommands that actually mutate the environment.

Helper Shortcuts

These are defined by the integration and map directly to the core commands:

# whip: Swiss Army knife for PATH management
whip cargo 5                 # prefer by index
whip cargo ~/.cargo/bin      # prefer by path (adds if needed!)
whip cargo toolchain stable  # prefer by fuzzy pattern
whip ~/.local/bin            # add path to PATH

# Other shortcuts
whia cargo                   # -> whi --all cargo
whiad ~/.local/bin ~/bin     # -> whi add ...
whim 12 1                    # -> whi move ...
whis 4 9                     # -> whi switch ...
whic                         # -> whi clean
whid 3 9                     # -> whi delete ...
whiu                         # -> whi undo
whiu 3                       # -> whi undo 3
whir                         # -> whi redo
whir 2                       # -> whi redo 2
whil work                    # -> whi load work
whiv PATH                    # -> whi var PATH
whiv -f                      # -> whi var -f (list all env vars)
whish                        # -> whi shorthands (show all shortcuts)

Use whichever spelling you prefer—both routes converge in Rust.

Persistence & State

• Saved PATH files live in ~/.whi/ (saved_path_bash, saved_path_zsh, saved_path_fish). whi apply all writes to all three. Each save creates a *.bak backup before overwriting. Files use a human-friendly directive format with !path.replace and !env.set sections (v0.6.0+). Legacy PATH!/ENV! format (pre-0.6.0) and colon-separated files (pre-0.6.0) are automatically detected and supported for backward compatibility.

• Profile storage lives in ~/.whi/profiles/. Each profile is a file in the same human-friendly format as saved PATH files. Use whi save <name> to save current PATH as a profile, whi load <name> to restore it, and whi list to see all profiles. You can manually edit these files - use !path.replace/!path.prepend/!path.append for PATH directives and !env.set/!env.replace/!env.unset for environment variables (all support shell variable expansion).

• Configuration lives in ~/.whi/config.toml. Auto-created on first run with defaults. Controls venv auto-activation and protected paths (preserved during whi apply to prevent breaking your shell).

• Session snapshots live in ${XDG_RUNTIME_DIR:-/tmp}/whi-<uid>/session_<ppid>.log (or session_<ppid>/<venv-dir-hash>.log when in a venv). Each PATH modification writes a snapshot (timestamp + full PATH string). The undo/redo system navigates through these snapshots with a cursor. Sessions keep up to 500 snapshots (initial + last 499) and auto-cleanup old sessions after 24 hours.

• Undo cursor lives in ${XDG_RUNTIME_DIR:-/tmp}/whi-<uid>/session_<ppid>.cursor (or session_<ppid>/<venv-dir-hash>.cursor when in a venv). Tracks your position in the snapshot history. No cursor file means you're at the latest state.

• Venv state (when active) is stored in ${XDG_RUNTIME_DIR:-/tmp}/whi-<uid>/session_<ppid>/venv_restore (PATH to restore on exit), venv_dir (venv directory path), and venv_exit_commands (any $source … <exit_command> hooks). This is session-specific - each terminal has independent venv state.

How undo/redo works

Every PATH mutation writes a snapshot. The undo system navigates backwards through snapshots, and redo moves forward. If you undo then make a new change, the "future" timeline is discarded (standard undo/redo behavior).

# Example session:
$ whi move 5 1              # snapshot 1 (initial is snapshot 0)
$ whi delete 3              # snapshot 2
$ whi undo                  # cursor moves to snapshot 1
$ whi undo                  # cursor moves to snapshot 0 (initial)
$ whi redo                  # cursor moves to snapshot 1
$ whi prefer cargo 2        # snapshot 3 (snapshot 2 discarded, new timeline)
$ whi reset                 # back to snapshot 0, cursor cleared

whi diff compares your current PATH to the initial session snapshot, so it shows all changes including manual export PATH=... modifications (not just whi operations).

Notes

• Mutating commands exit with an instructional message if the integration is missing. Copy the snippet shown, run it, and add it to your shell config for future sessions.

• The shell integration uses absolute paths to whi, so it continues to work even if PATH is modified or replaced during initialization.

• If you want to script against whi directly, capture stdout and export the string yourself. The integration just automates that for interactive use.

License

MIT License. See LICENSE for details.

Acknowledgments

• Prompt integration approach inspired by virtualenv. Thanks to the virtualenv team for their battle-tested solution using VIRTUAL_ENV and VIRTUAL_ENV_PROMPT environment variables that works seamlessly with modern prompt frameworks (Starship, oh-my-posh, Tide, etc.).
• The "whifile" name was inspired by just's "justfile" naming convention.