Croc is a command-line file transfer tool written in Go that enables secure peer-to-peer file sharing between any two computers. The project distinguishes itself by combining several capabilities that the maintainer claims are not all present together in other CLI file-transfer tools: it supports transfers between any two computers using a relay system, implements end-to-end encryption via password-authenticated key agreement (PAKE), works across Windows, Linux, and macOS platforms, handles multiple file transfers, allows resuming interrupted transfers, requires no local server or port-forwarding setup, prioritizes IPv6 with IPv4 fallback, and supports proxy usage including Tor.
The basic usage model is straightforward. To send files, a user runs croc with the target file or folder, which generates a code phrase that is automatically copied to the clipboard. The recipient runs croc with that same code phrase on another computer, and the transfer begins with end-to-end encryption established through the PAKE protocol. The tool supports numerous customization options including custom code phrases, automatic file overwriting, folder exclusion patterns, piping to stdin and stdout, QR code generation for mobile devices, and different elliptic curves and hash algorithms for encryption.
Installation is widely supported across platforms through multiple package managers. On macOS, users can install via Homebrew or MacPorts. Windows users have options including Scoop, Chocolatey, and Winget. The tool is also available through Nix, conda-forge, and Docker, with native packages for Alpine Linux, Arch Linux, Fedora, Gentoo, Termux, and FreeBSD. An Android version exists as a third-party F-Droid app. Users can also build from source using Go 1.22 or later.
Advanced features include self-hosting a relay server for users who want to avoid the default public relay, with customizable TCP ports and Docker support. The tool offers quiet mode for scripting and automation, clipboard management options, and the ability to send text and URLs directly. On Linux and macOS, the tool can be configured to pass the secret as an environment variable to prevent leaking it through process names, addressing CVE-2023-43621.
According to GitGenius activity tracking, the repository shows strong maintainer engagement with schollz handling 382 events across 158 tracked issues and pull requests. The median response latency for issues and PRs is 0.4 hours, though the mean is 129.3 hours, indicating some variation in response times. The most frequently labeled issues are bugs (46 occurrences), followed by no-issue-activity (29) and will-accept-pr (13), suggesting active bug tracking and openness to community contributions. The project has attracted contributors from major repositories including Microsoft's VSCode and TypeScript projects, as well as the Rust language repository, indicating its reach within the developer community.
