Still using bash in this day and age? Out-of-the-box modern shells: fish, nu, elvish

Preface

Linux servers generally default to bash as the shell, which isn't very smart. You can use a modern shell to improve the command-line experience.

zsh is a decent choice, but it's ugly by default and pairing it with Oh My Zsh is a hassle. This article covers installing and getting started with some of the newer, out-of-the-box shells.

If you use the chsh command to change the default login shell (Login Shell), some system scripts or automation tasks that depend on Bash-specific environment variables (such as settings in /etc/profile) may error out because they can't find the Bash environment.

Approach: launch the modern shell from within Bash.

Which of the three modern shells is strongest?

Each of the three has its own character—pick according to taste:

🐟 Fish

(Friendly Interactive SHell) The most hassle-free "all-rounder"

• Features: Ready out of the box. Built-in syntax highlighting, smart completions (based on your history and man pages), and very nice colors.
• Verdict: Easiest to pick up. If you don't want to mess with config and just want to get stronger the moment you install it, Fish is the first choice.
• Downsides: Although parts of the engine were rewritten starting with 4.0, it still isn't POSIX-compatible (for example, the VAR=val cmd syntax wasn't supported in older Fish).

🦀 Nushell

(Nu) The "futurist" that handles data like SQL

• Features: Everything is an object. In Nu, ls doesn't return a string of text—it returns a table. You can write things like ls | where size > 10mb.
• Verdict: The geekiest and most fun. It's not just a shell—it's more like a modern data-processing tool. If you often deal with JSON, CSV, or large batches of logs, it'll send you flying.
• Downsides: Steeper learning curve; some traditional command syntax takes getting used to.

🧝 Elvish

The programmer's "elegant language"

• Features: It tries to turn the shell into a real, powerful programming language. Supports complex structures (Map, List), and even has its own package manager.
• Verdict: The most solid, with the tightest logic. Suited for people who find Bash script syntax "hellish" and want to write scripts with a modern programming mindset.
• Downsides: Relatively smaller community ecosystem.

Tips

Nushell and Elvish are both cross-platform, meaning you can get a consistent experience on Windows, macOS, and Linux. As for Fish, I've only used it on Linux and haven't looked into whether it works on other systems.

Fish

Installing Fish

# Ubuntu/Debian
sudo apt update && sudo apt install fish -y

Installing Fisher (plugin manager)

This is currently the best tool for the job; I recommend installing it first. Run the following in fish:

curl -sL https://raw.githubusercontent.com/jorgebucaran/fisher/main/functions/fisher.fish | source && fisher install jorgebucaran/fisher

Configuring the launch logic

Add the following logic at the end of your ~/.bashrc file:

# 检查是否是交互式会话，且目标 shell 存在
if [[ $- == *i* ]] && command -v fish >/dev/null 2>&1; then
    exec fish
fi

• [[ $- == \*i\* ]]: Makes sure this only fires in an interactive command line (when you're operating it yourself). If a script is running without a terminal, it won't launch, so you don't break automation.
• exec: This word is crucial. It replaces the current process with a new one, so when you exit fish, the connection closes directly instead of dropping you back into a blank bash.

A few fun plugins/themes I recommend

Once Fisher is installed, you can run these commands to install some experience-boosting gems:

1. Pure (a clean, beautiful theme) fisher install pure-fish/pure A very clean, modern Prompt theme with excellent visuals.
2. Done (task-complete notifications) fisher install franciscolourenco/done If you run a long-running command (like a compile or backup), when it finishes it will send you a notification even if you're looking at another window.
3. Bass (Bash script compatibility) fisher install edc/bass This one matters most for you! Because Fish isn't compatible with Bash syntax, commands like source /etc/profile will error in Fish. After installing Bass, you can write bass source /etc/profile and it will handle the compatibility for you.

Quick tips

• Web UI configuration: Type fish_config in the Fish terminal. It will automatically pop up a browser page where you can click around to change color schemes and functions—very intuitive.
• Smart completions: Fish completions are based on your history. When you type the first few letters of a command, it shows a suggestion in gray; press the right arrow key (→) or Ctrl + F to fill it in.

I want them all

Nushell (Nu)

Data processing's "higher-dimensional strike"

Nushell is currently the most-discussed, most hardcore modern shell in the community. Its core logic is: everything is structured data.

Why is it fun?

In a traditional shell, ls outputs a string. If you want to filter by file size, you have to painfully slice that string with grep, awk, and cut. In Nushell, ls outputs an in-memory table.

Give it a try:

ls | where size > 10mb | sort-by type

It will filter files larger than 10MB and sort by type, just like SQL, and the output is still a neat table.

A JSON/YAML powerhouse: If you have a config.json, in Nu you just need:

open config.json | get database.port

It pulls the value out directly—no need to install jq at all.

Installation

https://www.nushell.sh/book/installation.html

Nushell is written in Rust and is very fast. You can download the binary directly or use a package manager.

wget -qO- https://apt.fury.io/nushell/gpg.key | sudo gpg --dearmor -o /etc/apt/keyrings/fury-nushell.gpg
echo "deb [signed-by=/etc/apt/keyrings/fury-nushell.gpg] https://apt.fury.io/nushell/ /" | sudo tee /etc/apt/sources.list.d/fury-nushell.list
sudo apt update
sudo apt install nushell

Elvish

The programmer's "Swiss army knife"

Elvish (elvish language) takes the extreme robustness and programming-friendly route. Its author is Chinese developer Qi Xiao, and the design philosophy is very rigorous.

Why is it fun?

• Pipes that don't break: In Bash, pipes carry a byte stream; in Elvish, pipes can carry complex data structures (lists, dictionaries).
• Built-in file manager: The history search UI with Ctrl+R is quite gorgeous; Ctrl+L enters a floating file-navigation mode similar to ranger, so you can pick files right in the shell.
• Extremely consistent syntax: It completely abandons Bash's fragmented syntax (like the difference between [ and [[); writing its scripts feels like writing a modern programming language.

Installation

https://elv.sh/get/package-manager.html

sudo apt install elvish

Configuring the launch logic

Put a selector in ~/.bashrc.

Every time you log in it will ask which shell you want to use (personally I'd just go with fish—it works out of the box)

# 交互模式下询问你想进入哪个宇宙
if [[ $- == *i* ]]; then
    echo "Choose your shell: [1] Fish  [2] Nushell  [3] Elvish  [Any] Stay in Bash"
    read -n 1 -p "Select: " choice
    echo
    case $choice in
        1) exec fish ;;
        2) exec nu ;;
        3) exec elvish ;;
        *) echo "Welcome back to Bash." ;;
    esac
fi