Programming Sans Internet

The Internet is down
The internet is down

Software development is tightly coupled to the internet. Some programs refuse to run or fail catastrophically without an internet connection. For most people a computer becomes a useless pile of metal without an internet connection.

Lately, my circumstances have required the dreaded skill of programming without the internet. The This blog post was completed just before the power company tripped over itself. and Here's to hoping that the Starlink project becomes successful and affordable. infrastructure in my country royally sucks. Keeping in a state of “flow” when the internet goes down is extremely difficult. Let’s take a look at my basic approach to remedying the difficulty of programming without an internet connection when its absolutely needed.

Offline The Documentation

There are many kind people in the world. Some of them write manuals that no one really reads. Linux based distributions have first class support for POSIX style programming. One could simply run the command man to bring up any function or program instruction in the POSIX programmer’s manual. If we wanted to know how to use mmap we could simply run man mmap.

Manpage for mmap
Manpage for mmap

Manpages are considered so old school now that it’s somewhat rare to see anyone using man let alone Manpages can be made with the troff and groff typsetting family of programs. localized manuals.

“Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it. When we enquire into any subject, the first thing we have to do is to know what books have treated of it. This leads us to look at catalogues, and at the backs of books in libraries.” Samuel Johnson, The Life of Samuel Johnson

Manpages are faster than a search engine lookup — but only if you know what you are looking for. Search engine lookups can be expensive Multitasking. There is a mental cost to every context switch. switching actions, but you often get what you’re looking for quickly.

Good manuals contain a synopsis of a program or function, an example of its usage pattern, return value references, and most important of them all — error handling instructions.

Ensure you have manpages for all tools and target languages that you are working with if available. Check your local distribution’s repository to see if there are any extra manuals available.

Run man -k . to see On NixOS man is broken. You'll need to wire up mandb or wait until release 20.09. current manuals on the system. Display all manuals containing a keyword with man -k <keyword>.

PDF version of mmap's manpage PDF version of mmap's manpage manuals to PDF format by using man -Tpdf <keyword>. Pipe the output into the PDF reader of choice.

man -Tpdf mmap | zathura -

Offline The Wiki

The Arch Wiki is a very well known and respected documentation source. If you find a wiki that you visit more than once — offline it immediately. Relegate any downloaded wiki to a directory where you can grep through the files quickly and easily.

This applies doubly for any GitHub wiki. Extract markdown copies of a repository’s wiki by using the git clone command.

git clone https://github.com/koalaman/shellcheck.wiki.git

GitHub’s pull requests and issues contain critical information. Grab all pull requests and issues from any working It goes without saying that there should be an offline copy of any repository you work with. using the Github API (Application Programming Interface).

https://api.github.com/repos/<repo-owner>/<repo-name>/issues?state=all
https://api.github.com/repos/<repo-owner>/<repo-name>/pulls?state=all

Offline The REPLs

REPL stands for read, evaluate, print, and loop. It’s basically the equivalent of a command line shell for a specified language. Get comfortable using a REPL just like any other familiar shell to reduce internet lookups and context switching.

Most of us use our heads as rudimentary REPLs. Basically, we write a piece of code with the general expectation of its action and return state.

Eventually you’ll reach a point where you’re doing that weird JavaScript style crash and burn programming. The target code is now large enough that it can’t fit inside your head, so you’ll edit what you approximate is wrong, and run it again to see if it doesn’t crash and burn. Repeat ad nauseam.

Unpacking a tricky error state is often much quicker in a REPL than with an internet search or using a crude crash and burn method. This saves time and having to context switch to a search lookup for some common or obscure error message. Make sure to have all REPLs offline for any language or tool you use regularly if available.

Elixir's REPL
Messing around with Elixir's REPL iex in Vim

Offline The Static Code Analysis

Static code analysis offers refactoring advice, sniffing out high level coding errors, and correcting naive approaches to a problem. Static code analysis tools can hold your hand and carry you a good distance.

In fact, there are some static analysis tools that are so Haskell's ghc and hlint as well as Shell's shellcheck. that if you have good cursory knowledge of a language, you can learn the ins and outs quicker than reading a book.

The authors of static code analysis tools know more than you — it’s as simple as that. Static analysis coalesces a collection of common questions, answers, and pitfalls that many experienced people have encountered time and time again.

Even programs that are configured with How many of us are familiar with vulnerabilities such as HTTP request and response splitting? files like Nginx have their own static analysis code tools like gixy. Ensure you have all static analysis tools for any language or program that you work with regularly offline.

Offline The Editor

Most people use integrated development environments (IDE) nowadays which probably handles most or all of the above (with or without internet probably), but in a situation without an internet connection having an editor that is flexible is paramount.

This means an editor like vim or emacs. In the jungle, you don’t have the luxury of downloading a plugin or extra feature to assist you. Flexible editors have configuration that is dynamic enough to code your own plugins trivially on the fly.

Emacs is written in Emacs Lisp, and Vim uses Vimscript. Vim itself has one of the most thorough manuals in existence, so implementing an ad hoc plugin for an odd workflow is not too difficult as long as you know how to read.

Updated 30 July 2020