eltclsh vs fish (Friendly Interactive SHell)

Tcl is a saner scripting language built on the same principle as the Unix shell (everything is a string) with more than a hint of Lisp. eltclsh makes it possible to use Tcl interactively with tab completion for both language constructs and file paths. The result is that you can develop a snippet of Tcl code interactively and then paste it in your script.

TclVFS allows you access files inside ZIP archives or on remote HTTP and FTP servers like you would local files. If you put "package require vfs::urltype; vfs::urltype::Mount http"
in your ~/.eltclshrc you can do things like "file copy http://example.com/file /tmp/file" (HTTPS is currently not supported by TclVFS.)

fish suggests commands as you type, based on command history, completions, and valid file paths. As you type commands, you will see a completion offered after the cursor, in a muted gray color (which can be changed with the fish_color_autosuggestion variable). However, you can NEVER turn them off!

It has a great tutorial. And the official documentation is clear, full of eloquent examples, and to the point.

While other shells require a lot of set up to act the way you want them to and to have some useful features, fish works perfectly out of the box. It has all the most widely used features baked in and are there out of the box without having the need to install plugins or tweak any configuration files.

Everything you need from oh-my-zsh is available on default fish, don't need to install any plugins. And even better, fish is smaller than zsh.

You can define Universal variables, which are shared instantaneously through all running fish sessions and persists through shell restarts.

Fish has by far the best way to work with history, everything is automatically searchable. It works in the way you expect. No learning required.

Fish_update_completions parses manual pages installed on the system, and attempts to create completion files in the fish configuration directory.

Large test coverage, micro-second shell start, compatibility with plugins from other existing frameworks such as Tackle, Oh My Fish and Wahoo, cache system, offline index, the Fishery and other features.

Unlike bash, this won't return you string *.sh if no .sh files are found

for filename in *.sh
    echo "$filename"
end

Here is a sample. Notice that there are 2 files with spaces in names. ls produces a valid list, and for loop correctly iterated through its values.

➤ for a in (ls); ls -l $a; end
-rw-rw-r-- 1 sashka sashka 0 Apr 19 03:16 alma mater.txt
-rw-rw-r-- 1 sashka sashka 0 Apr 19 03:16 whatever i want.txt

sh scripts tend to be fragile when there are lists containing values with spaces.

Also:

➤ echo $PATH
/usr/bin /bin /usr/sbin /sbin /usr/local/bin
➤ echo $PATH[1]
/usr/bin
➤ echo $PATH[-1]
/usr/local/bin

Because it needs very little configuration to work properly, you can use Fish everywhere. If you are working on a system you don't usually work, installing Fish from the repository is easy and will give you the same experience as the installation on your own machine without having to drag a dotfile around.

When writing functions in an interactive shell, it will auto-indent as needed for if, for, function, etc.

The following, for example:

for file in (find . -name "*.foo" -type f)
fgrep -H "something" $file
echo "hello" $file
end | grep -v "hello"

Will run the for loop, take all the stdout from it (both the fgrep and echo), and then pipe it through the final grep command.

Fish community maintains Oh My Fish, which is a shell framework inspired on Oh My Zsh awesome design and name. It offer a lot of beautiful prompt themes and awesome plugins, is lightweight, awesome and very simple to use.