DASH vs Ion (shell)

Dash has a very fast startup, this happens because the shell is started a lot of times during boot and dash minimizes the work it does during this process.

It is designed to be very lightweight and has no support for shell specific extensions that are not POSIX.

DASH is the default shell for Debian based systems due to it speed, full POSIX compliance and low overhead.

It's fully POSIX compatible, so if your script runs on dash it will probably run on all other shells.

It's a clone of the original System V4 Bourne shell.

All variable assignments may optionally specify a type, which will enforce that the supplies value is compatible with that type before storing it, returning an error if there's a mis-match.

Arrays are sliced by elements, and strings are sliced by graphemes.

The entire Rust ecosystem is known for having excellent, modern documentation, and Ion is no exception. Couple that with it having far less cruft (ie fewer things to learn) some syntactic and conceptual inspiration from Rust, and suddenly you have a very easy to learn (and still very powerful) shell.

Generally more type-safe, enabling explicitness, and allowing for powerful slicing and method syntax.

Ion actually manages to be faster than Dash -- simultaneously using less memory and packing much more functionality.

Syntax is much simpler than other shells, leading to very elegant and succinct scripts and command invocations.

Shells written in C are often riddled with memory-based vulnerabilities that lead to high profile security flaws that are continually discovered decades later. GNU Bash's Shellshock vulnerability, for example, is an example of a vulnerability that Rust prevents. Rust raises the bar for minimum code quality standards by enforcing various restrictions on type/variable usage, and therefore Ion provides a high quality code base from the start.

There are no dependencies on C or C libraries (except for the minimum required to run on Linux). By opting for the MUSL target toolchain, a fully static binary can be generated and distributed to systems.

It is exceptionally easy to use 24-bit colors in the shell with Ion's c/color namespace.

echo ${c::0x09F}Bluish text${c::0x630bg}with a brownish background${c::reset}

Offers a unique concept of string and array methods, whereby invoking the name of a method, and supplying arguments to it, you can perform otherwise complex text manipulation at expansion time. Also supports recursively processing the results of method expansions within method expansions.

A special syntax allows for obtaining values from within special namespaces -- either namespaces that are built into the shell, such as the color namespace, or from plugins, such as the git plugin.

Plugins may be integrated within Ion using a C FFI. These plugins can add additional methods and namespaces.

Ion shell is featured within the distributed Concurr application, by the same author of Ion, which creates embedded instances of the Ion shell in the server for executing commands locally.