Best Free and Open Source Software

posted by Rianne Schestowitz on Jan 03, 2026

• ktlint - Kotlin linter with built-in formatter - LinuxLinks

  ktlint is a Kotlin linter in spirit of feross/standard (JavaScript) and gofmt (Go).

  This is free and open source software.

• tinycss2 - CSS parser and generator - LinuxLinks

  tinycss2 is a low-level CSS parser and generator written in Python: it can parse strings, return objects representing tokens and blocks, and generate CSS strings corresponding to these objects.

  Based on the CSS Syntax Level 3 specification, tinycss2 knows the grammar of CSS but doesn’t know specific rules, properties or values supported in various CSS modules.

  This is free and open source software.

• gsh - POSIX-compatible, Generative Shell - LinuxLinks

  gsh is a modern, POSIX-compatible, generative shell that’s in an early stage of development.

  By generative, the developer means gsh will automatically suggest the next command you’re likely to want to run, and will provide an explanation of the command you are about to run.

  This is free and open source software.

• SoS - data collection tool - LinuxLinks

  SoS is an extensible, portable, support data collection tool primarily aimed at Linux distributions and other UNIX-like operating systems.

  This is free and open source software.

• cpx - CLI for C++ that unifies the fragmented C++ ecosystem - LinuxLinks

  cpx is a batteries-included CLI for C++ that unifies the fragmented C++ ecosystem. It provides a cohesive, Cargo-like experience for managing projects, dependencies, and builds, regardless of your underlying build system.

  This is free and open source software.

• zuse - terminal IRC client - LinuxLinks

  ZUSE is a sleek, minimal IRC client for your terminal. Built with Go and powered by the elegant Bubble Tea framework. Chat faster, cleaner, and without distractions right from your terminal.

  This is free and open source software.

• Psalm - static analysis tool - LinuxLinks

  Psalm is a static analysis tool that attempts to dig into your program and find as many type-related bugs as possible.

  It has a few features that go further than other similar tools:

  Mixed type warnings – if Psalm cannot infer a type for an expression then it uses a mixed placeholder type. mixed types can sometimes mask bugs, so keeping track of them helps you avoid a number of common pitfalls. Intelligent logic checks – Psalm keeps track of logical assertions made about your code, so if ($a && $a) {} and if ($a && !$a) {} are both treated as issues. Psalm also keeps track of logical assertions made in prior code paths, preventing issues like if ($a) {} elseif ($a) {}. Property initialisation checks – Psalm checks that all properties of a given object have values after the constructor is called. Taint analysis – Psalm can detect security vulnerabilities in your code. Language Server – Psalm has a Language Server that’s compatible with a range of different IDEs. Automatic fixes – Psalm can fix many of the issues it finds automatically. Automatic refactoring – Psalm can also perform simple refactors from the command line.

  This is free and open source software.

• 7 Best Free and Open Source PHP Linter Tools - LinuxLinks

  Linters are useful tools for maintaining code quality and consistency in your PHP applications. They analyze code for potential issues, enforce coding standards, and help catch errors before they are pushed into production. Linters are not necessarily a quick fix, can be a distraction, and it’s not inconceivable that they may not be helpful with old, large code bases.

  This article picks some useful tools to help you fix PHP code. Here’s our verdict captured in a legendary LinuxLinks-style ratings chart. Only free and open source software is eligible for inclusion.

• OpenSSH GUI - graphical frontend - LinuxLinks

  OpenSSH GUI is a frontend for managing your SSH Keys – on Linux, macOS, and Windows.

  The primary reason for creating this project was to give “end-users” a modern looking GUI for managing their SSH Keys – and making it easier to deploy them to a server of their choice.

  This is free and open source software.

• Garden - command runner and multi-repo Git configuration tool - LinuxLinks

  Garden is a simple yet expressive command runner and multi-repo Git configuration tool.

  Garden helps you create development workflows over collections of self-contained, loosely-coupled and inter-dependent Git worktrees.

  This is free and open source software.