I have a few old standards in my toolbelt that I find myself calling upon most often, but I try to learn enough about many programming languages to reason about whether or not they’re suitable to any use-case I’m thinking about. The best way is to learn by doing, so getting a general impression of the utility of many languages helps equip you with the knowledge of whether or not they’d be useful for a particular problem even if you don’t know them yet.

Only included are languages which I feel knowledgable enough about to comment on, there are many that aren’t here and which I encourage you to research.

C

Pros: good performance, access to low-level tooling, useful in systems programming, statically typed, standardized and venerable, the lingua franca, universal support on all platforms.

Cons: string munging, extensible programming, poor availability of ergonomic libraries in certain domains, has footguns, some programmers in the wild think the footguns are useful.

Go

Pros: fast, conservative, good package manager and a healthy ecosystem, standard library is well designed, best in class for many problems, has a spec and multiple useful implementations, easy interop with C.

Cons: the runtime is too complicated, no distinction between green threads and real threads (meaning all programs deal with the problems of the latter).

Rust

Pros: it’s SAFE, useful for systems programming, better than C++, ecosystem which is diverse but just short of the npm disease, easy interop with C.

Cons: far too big, non-standardized, only one meaningful implementation.

Python

Pros: easy and fast to get things done, diverse package ecosystem of reasonably well designed packages, deeply extensible, useful for server-side web software.

Cons: bloated, poor performance, dynamically typed, cpython internals being available to programmers has led to an implementation monoculture.

JavaScript

* and all of its derivatives, which ultimately inherit its problems.

Pros: functional but with an expressive and C-like syntax, ES6 improved on many fronts, async/await/promises are well designed, no threading.

Cons: dynamic types, package ecosystem is a flaming pile, many JS programmers aren’t very good at it and they make ecosystem-defining libraries anyway, born in web browsers and inherited their many flaws.

Java

* and all of its derivatives, which ultimately inherit its problems.

Pros: has had enough long-term investment to be well understood and reasonably fast.

Cons: hella boilerplate, missing lots of useful things, package management, XML is everywhere, not useful for low-level programming (this applies to all Java-family languages).

C#

Pros: less boilerplate than Java, reasonably healthy package ecosystem, good access to low level tools for interop with C, async/await started here.

Cons: ecosystem is in turmoil because Microsoft cannot hold a singular vision, they became open-source too late and screwed over Mono.

Haskell

* and every other functional-oriented programming language in its class, such as elixir, erlang, most lisps, even if they resent being lumped together

Pros: it’s FUNCTIONAL, reasonably fast, useful when the answer to your problem is more important than the means by which you find it, good for research-grade compilers.

Cons: it’s FUNCTIONAL, somewhat inscrutable, awful package management, does not fit well into its environment, written by people who wish the world could be described with a pure function and design software as if it could.

Perl

Pros: entertaining, best in class at regexes/string munging, useful for making hacky kludges when such solutions are appropriate.

Cons: inscrutable, too extensible, too much junk/jank.

Lua

Pros: embeddable & easily plugged into its host, fairly simple, portable.

Cons: 1-based indexing is objectively bad, the upstream maintainers are kind of doing their own thing and no one really likes it.

POSIX Shell scripts

Pros: nothing can string together commands better, if you learn 90% of it then you can make pretty nice and expressive programs with it for a certain class of problem, standardized (I do not use bash).

Cons: most people learn only 10% of it and therefore make pretty bad and unintuitive programs with it, not useful for most complex tasks.

Disclaimer: I don’t like the rest of these programming languages and would not use them to solve any problem. If you don’t want your sacred cow gored, leave here.

C++

Pros: none

Cons: ill-defined, far too big, Object Oriented Programming, loads of baggage, ecosystem that buys into its crap, enjoyed by bad programmers.

PHP

Pros: none

Cons: every PHP programmer is bad at programming, the language is designed to accommodate them with convenient footguns (or faceguns) at every step, and the ecosystem is accordingly bad. No, PHP7 doesn’t fix this. Use a real programming language, jerk.

Ruby

Pros: It’s both ENTERPRISE and HIP at the same time, and therefore effective at herding a group of junior to mid-level programmers in a certain direction, namely towards your startup’s exit.

Cons: bloated, awful performance, before Node.js took off this is what all of those programmers used.

Scala

Pros: more expressive than Java, useful for Big Data problems.

Cons: Java derivative, type system requires a PhD to comprehend, too siloed from Java, meaning it gets all of the disadvantages of being a Java ecosystem member but few of the advantages. The type system is so needlessly complicated that it basically cripples the language on its own merits alone.