Fish Shell

Fish (friendly interactive shell) is a free and open-source Unix shell that focuses on interactivity, usability, and user-friendliness, providing many features out of the box that other shells (bash, zsh) require plugins or configuration to achieve. Originally created by Axel Liljencrantz in 2005 and rewritten in Rust as version 4.0 (2024), Fish is designed to be 'excellent out of the box' without requiring extensive configuration. Key features: syntax highlighting: Fish provides real-time syntax highlighting as you type, showing valid commands in green, errors in red, valid paths with underlines, and quoted strings, options, and operators in distinct colors. This provides immediate feedback before pressing Enter. Autosuggestions: Fish automatically suggests commands based on command history and valid completions, displayed in gray text as you type. Press the right arrow key to accept the suggestion. Tab completion: powerful, context-aware tab completion for commands, options, file paths, variables, processes, and more. Fish includes built-in completions for hundreds of common commands, generated from their man pages. No configuration required. Scripting: Fish has a clean, consistent scripting syntax that differs from POSIX sh/bash. Notable differences: no subshells ($) for variables (set var value), conditional blocks use if/else/end, loops use for/end, functions use function/end, and command substitution uses (command) instead of $(command). Universal variables: variables that are shared across all Fish sessions and persist across reboots (set -U). Web-based configuration: the 'fish_config' command opens a web browser with a graphical interface for customizing prompt theme, colors, syntax highlighting, variables, and key bindings. Abbreviations: expand short words into longer commands (e.g., 'gc' expands to 'git commit'). Vi mode: optional Vim-style keybindings for command-line editing. Cross-platform: Linux, macOS, BSD, Windows (WSL). GPLv2.