bash-autosuggestions

Fish-like autosuggestions for Bash — suggests commands as you type based on history.

Inspired by zsh-autosuggestions and fish shell, this pure-Bash script shows inline "ghost text" suggestions from your command history as you type.

How It Works

As you type, a dimmed suggestion appears after your cursor showing the most recent matching command from history. The suggestion is non-intrusive — it won't execute unless you explicitly accept it.

$ kubectl get po▌ds -n production -o wide
              ↑ ghost text (dimmed gray)

Keybindings

Key	Action
→ (Right Arrow)	Accept full suggestion
End	Accept full suggestion
Alt+→ / Alt+F	Accept next word
↑ (Up Arrow)	Cycle to next suggestion (or history if no suggestions)
↓ (Down Arrow)	Cycle to previous suggestion (or history if no suggestions)
Ctrl+]	Dismiss suggestion
Any typing	Suggestion updates live

Requirements

• Bash 4.0+ (check with bash --version)
• Terminal with ANSI color support (virtually all modern terminals)

Installation

Quick Install

git clone https://github.com/YOUR_USER/bash-autosuggestions.git
cd bash-autosuggestions
bash install.sh
source ~/.bashrc

Manual Install

# Copy the script somewhere permanent
mkdir -p ~/.local/share/bash-autosuggestions
cp bash-autosuggestions.sh ~/.local/share/bash-autosuggestions/

# Add to your .bashrc
echo 'source ~/.local/share/bash-autosuggestions/bash-autosuggestions.sh' >> ~/.bashrc

# Reload
source ~/.bashrc

One-liner (download + install)

curl -sL https://raw.githubusercontent.com/YOUR_USER/bash-autosuggestions/main/bash-autosuggestions.sh \
  -o ~/.local/share/bash-autosuggestions/bash-autosuggestions.sh --create-dirs && \
  echo 'source ~/.local/share/bash-autosuggestions/bash-autosuggestions.sh' >> ~/.bashrc && \
  source ~/.bashrc

Configuration

Set these variables before sourcing the script in your .bashrc:

# Color of the ghost suggestion (ANSI SGR code)
# Default: "38;5;244" (medium gray)
# Examples:
#   "38;5;240"         - darker gray
#   "38;5;248"         - lighter gray
#   "38;2;100;100;100" - 24-bit RGB gray
#   "2"                - dim text
BASH_AUTOSUGGEST_HIGHLIGHT="38;5;244"

# Strategy for finding suggestions
# "history"        - most recent history match (default)
# "match_prev_cmd" - match conditioned on previous command
BASH_AUTOSUGGEST_STRATEGY="history"

# Ignore history entries matching this glob pattern
# Example: "cd *" to never suggest cd commands
BASH_AUTOSUGGEST_HISTORY_IGNORE=""

# Minimum input length before suggesting (default: 1)
BASH_AUTOSUGGEST_MIN_LENGTH=1

# Maximum number of candidates to collect (default: 50)
BASH_AUTOSUGGEST_MAX_CANDIDATES=50

source ~/.local/share/bash-autosuggestions/bash-autosuggestions.sh

Strategies

history (default)

Suggests the most recent command from history that starts with your current input.

match_prev_cmd

Like history, but prioritizes matches whose preceding history entry matches the command you just ran. This provides context-aware suggestions — e.g., after running git add ., it'll suggest git commit -m "..." if that's what you typically do next.

Falls back to history strategy if no contextual match is found.

Disabling at Runtime

# Disable autosuggestions in the current shell (removes all bindings)
bash_autosuggest_disable

# Re-enable autosuggestions
bash_autosuggest_enable

# Toggle on/off (lightweight - keeps bindings)
bash_autosuggest_toggle

Uninstalling

bash uninstall.sh

Or manually:

# Remove from .bashrc (delete the source line)
# Remove installed files
rm -rf ~/.local/share/bash-autosuggestions

Comparison with Alternatives

Feature	bash-autosuggestions	ble.sh	zsh-autosuggestions
Shell	Bash	Bash	Zsh
Inline suggestions	✅	✅	✅
Multiple suggestions cycling	✅ (Up/Down arrows)	✅	❌
Suggestion counter [N/M]	✅	❌	❌
Syntax highlighting	❌	✅	❌ (separate plugin)
Partial accept (word)	✅	✅	✅
History strategy	✅	✅	✅
Completion strategy	❌	✅	✅
match_prev_cmd	✅	❌	✅
Pure Bash	✅	✅	N/A (Zsh)
Lightweight	✅ (~470 LOC)	❌ (large)	✅
Vim mode	❌	✅	❌
Install complexity	Low	Medium	Low

When to use this: You want a lightweight, single-file, drop-in solution that adds fish-like history suggestions to Bash without replacing the entire line editor.

When to use ble.sh instead: You want a full-featured Bash line editor with syntax highlighting, advanced completion, vim modes, and more. ble.sh is a much larger and more capable project.

Troubleshooting

Suggestions don't appear

• Ensure Bash 4.0+: echo $BASH_VERSION
• Check your history is non-empty: history | wc -l
• Ensure HISTFILE is set and readable
• Make sure the script is sourced (not executed): source bash-autosuggestions.sh

Ghost text artifacts remain on screen

• Run reset or press Ctrl+L to refresh the terminal
• This can happen if the terminal is resized during a suggestion

Conflicts with other readline customizations

• Source bash-autosuggestions.sh after other .inputrc or bind customizations
• If using fzf, source fzf's keybindings first

Arrow keys produce garbage text

• Your terminal may use different escape sequences
• Check with cat -v then press the arrow key
• Adjust the bind -x entries in _bas_setup if needed

How It Works (Technical)

The script uses Bash's bind command to create macros for every printable character. Each macro inserts the character normally, then triggers an internal function (_bas_update) via Ctrl+_. This function:

1. Reads the current READLINE_LINE (what the user has typed)
2. Searches history in reverse for the most recent match
3. Renders the untyped suffix as "ghost text" using ANSI escape codes (save cursor → print dimmed text → restore cursor)

Accept keys (→, End, Alt+→) modify READLINE_LINE and READLINE_POINT directly to insert the suggestion.

License

MIT