luajit is small, fast(well, it can jit), and has a small but complete standard library and can do FFI pretty easily, should be ideal for most homelab usecase

ldd $(which luajit)                                                                                
        linux-vdso.so.1 (0x00007ffee9dc7000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fb4db618000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fb4db613000)
        libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fb4db5f3000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb4db3ca000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fb4db799000)

I don’t have python (or even bash) available in all my systems, and so my goto language for script is usually sh (yes, posix sh), which in all honestly is quite frustrating for manipulating data.

Why are you making it hard on yourself? apt/dnf install a language to use and use it.

I honestly love Powershell, but haven’t tried the Linux version yet. I only use Bash on linux but it has a load of odd quirks that make it unpleasant to use imo. Can’t comment on anything else.

What about Lua/Luajit?

In most scripting languages you have the interpreter binary and the (standard) libraries as separate files. But creating self-extracting executables, that clean up after themselves can easily be done by wrapping them in a shell script.

IMO, if low dependencies and small size is really important, you could also just write your script in a low level compiled language (C, Rust, Zig, …), link it statically (e.g. with musl) and execute that.

Perl is already installed on most linux machines and unless you start delving into module usage, you won’t need to install anything else.

Python is more fashionable, but needs installing on the host and environments can get complicated. I don’t think it scales as well as Perl, if that’s a concern of yours.

Technically, you could bundle a Perl script with the interpreter on another system using pp and run the packed version on systems with no installed Perl, but at that point you might as well just use a compiled language.

I don’t know if it matches your desire for easy install of small disk space, but it might make up for it in other arenas - Ruby is my new-found love when making simple scripts. Being able to mostly emulate the shell integration that bash has by just using backticks to call a shell command is the killer feature in my book.

Maybe something like Elvish or Nushell could be worth a look. They have a lot of similarities to classic shells like bash, but an improved syntax and more powerful features. Basically something in between bash and Python. Not sure about disk footprint or general availability/portability though

Realistically whatever problems you see in python will be there for any other language. Python is the most ubiquitously available thing after bash for a reason.

Also you mentioned provisioning scripts, is that Ansible? If so python is already there, if you mean really just bash scripts I can tell you that does not scale well. Also if you already have some scriptsz what language are they on? Why not write the function there?

Also you’re running syncthing on these machines, I don’t think python is larger than that (but I might be wrong).

Python.

Just remember to use pyenv for interpreter installation, version and environment management. It’s pretty straightforward that way and you have predictability.

Don’t ever manually fiddle with the system python and/or libraries or you’ll break your system. You should just rely on the package manager for that.

posix sh + awk for manipulating data?

guile scheme or Julia

I would go with Guile, because it is built-in to the Guix Package Manager which is a really good general-purpose package manager.

It ticks several of your boxes:

• has a CLI interpreter
• is a general purpose language, Scheme, amd compliant with revisions 5, 6, and 7 of the language standard
• allows writing in a functional style (it is one of the original functional programming languages)
• small disk footprint, but still large enough to be “batteries included”
• decent documentation, especially if you use Emacs
• simple setup: not so much, unless you are using Guix to begin with. The standard distribution ships with lots of pre-built bytecode files, you need an installer script to install everything.

It also has pretty good libraries for system maintenance and reporting:

• File-Tree-Walk
• A simple web server
• XML parsing

Tried bash, Make, and awk/sed. All hit brick walls. Finally landed on pyinvoke. Two dependencies to install on any new machine. Never had problems. Also, easy to debug and modify as projects evolve.

JavaScript through Node.js, or TypeScript through Deno if you like typed languages. They both check all your boxes (just check the size of the executables to make sure that it’s what you would consider “small footprint”).

Both languages and runtimes are quite popular, so you will find any answers on StackOverflow.

They are both single-executable with little dependencies, and Deno can also compile your scripts to self-contained executables.

As a bonus, both support the vast and extensive NPM package repository where you can find all sort of libraries for even the most complex tasks.

And they work with your favourite IDE or editor, not just syntax highlighting, but also contextual suggestions.