Bob

Bob is a Fish shell plugin that keeps your command history tidy by automatically removing mistyped or otherwise unwanted commands.

This project is based on Sponge (originally by Andrei Borisov) and is released under the MIT License.

This version includes bug fixes and a substantial refactor to reduce global state, improve Fisher-based uninstallability, and fixes a history-search bug present in the original Sponge implementation.

🛠️ Installation

Install with Fisher:

fisher install enklht/bob

🤔 What it does

Use your shell normally; Bob runs in the background and keeps your history clean. It:

• Automatically filters out failed commands (unless the same command was previously successful and allowed).
• Keeps a small buffer of recent commands (default: 2) so you can quickly re-run or correct mistakes.
• Lets you add custom filters to exclude commands by pattern or custom logic.

📝 Note 📝 :
Bob does not remove commands that failed before installation. If you want to clear all previous history, you can reset it with (this clears the entire history regardless of exit status. Be careful):

history clear

⚙️ Configuration

All configuration is done via Fish variables. You can place these in your config.fish or set them interactively.

Delay before purging

Bob keeps recent commands for a short delay so you can still access them via history. Adjust the delay with:

set bob_delay 5

To keep the session history intact until you exit the shell:

set bob_purge_only_on_exit true

Built-in filters

Bob ships with two filters by default:

• bob_filter_failed: filters out commands with non-zero exit codes (configurable).
• bob_filter_matched: filters commands that match one or more regex patterns.

Configuration examples (which filter they apply to):

• Settings for bob_filter_failed:

# Which exit codes are treated as successful by bob_filter_failed
# default: 0
set bob_successful_exit_codes 0 127

# If false, bob_filter_failed will filter out failed commands even if they
# were previously successful (i.e., present earlier in history).
# default: true
set bob_allow_previously_successful false

• Settings for bob_filter_matched:

# Regex patterns used by bob_filter_matched; any matching command will be filtered.
# default: empty
set bob_regex_patterns '(?:\d{1,3}\.){3}\d{1,3}'

Custom filters

You can add custom filters. A filter is a Fish function that receives two positional arguments:

1. command: the exact command string entered
2. exit_code: the command's exit status

Return exit status 0 to filter (remove) the command, or a non-zero value to keep it in history. You can define your custom filter in config.fish or in the functions directory as a standalone function.

Register your filter by appending its name to bob_filters:

set --append bob_filters your_awesome_filter

Example custom filter

This example demonstrates a custom filter that removes commands from history when the current working directory is under /tmp. A filter should return 0 to filter (remove) the command, or a non-zero status to keep it.

function filter_tmp -a command exit_code
  # If the current directory is /tmp or a subdirectory, filter the command.
  if string match -rq '^/tmp($|/)' (pwd)
    return
  end

  # Otherwise, keep the command in history.
  return 1
end

After defining the function (e.g., in your config.fish or a functions file), register it:

set --append bob_filters filter_tmp

⚠️ Be careful ⚠️ :
Filters run after every command, so avoid slow operations in filters.

🤝 Contributing and origin

This project is derived from Sponge. Contributions, bug reports, and pull requests are welcome.

©️ License

Originally distributed under the MIT License by Andrei Borisov (2020). Modifications by enklht (2025).

MIT