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## About `croc` is a tool that allows any two computers to simply and securely transfer files and folders. AFAIK, *croc* is the only CLI file-transfer tool that does **all** of the following: - Allows **any two computers** to transfer data (using a relay) - Provides **end-to-end encryption** (using PAKE) - Enables easy **cross-platform** transfers (Windows, Linux, Mac) - Allows **multiple file** transfers - Allows **resuming transfers** that are interrupted - No need for local server or port-forwarding - **IPv6-first** with IPv4 fallback - Can **use a proxy**, like Tor For more information about `croc`, see [my blog post](https://schollz.com/tinker/croc6/) or read a [recent interview I did](https://console.substack.com/p/console-91).  ## Install You can download [the latest release for your system](https://github.com/schollz/croc/releases/latest), or install a release from the command-line: ```bash curl https://getcroc.schollz.com | bash ``` ### On macOS Using [Homebrew](https://brew.sh/): ```bash brew install croc ``` Using [MacPorts](https://www.macports.org/): ```bash sudo port selfupdate sudo port install croc ``` ### On Windows You can install the latest release with [Scoop](https://scoop.sh/), [Chocolatey](https://chocolatey.org/), or [Winget](https://learn.microsoft.com/windows/package-manager/): ```bash scoop install croc ``` ```bash choco install croc ``` ```bash winget install schollz.croc ``` ### Using nix-env You can install the latest release with [Nix](https://nixos.org/): ```bash nix-env -i croc ``` ### On NixOS You can add this to your [configuration.nix](https://nixos.org/manual/nixos/stable/#ch-configuration): ```nix environment.systemPackages = [ pkgs.croc ]; ``` ### On Alpine Linux First, install dependencies: ```bash apk add bash coreutils wget -qO- https://getcroc.schollz.com | bash ``` ### On Arch Linux Install with `pacman`: ```bash pacman -S croc ``` ### On Fedora Install with `dnf`: ```bash dnf install croc ``` ### On Gentoo Install with `portage`: ```bash emerge net-misc/croc ``` ### On Termux Install with `pkg`: ```bash pkg install croc ``` ### On FreeBSD Install with `pkg`: ```bash pkg install croc ``` ### On Linux, macOS, and Windows via Conda You can install from [conda-forge](https://github.com/conda-forge/croc-feedstock) globally with [`pixi`](https://pixi.sh/): ```bash pixi global install croc ``` Or install into a particular environment with [`conda`](https://docs.conda.io/projects/conda/): ```bash conda install --channel conda-forge croc ``` ### On Linux, macOS via Docker Add the following one-liner function to your ~/.profile (works with any POSIX-compliant shell): ```bash croc() { [ $# -eq 0 ] && set -- ""; docker run --rm -it --user "$(id -u):$(id -g)" -v "$(pwd):/c" -v "$HOME/.config/croc:/.config/croc" -w /c -e CROC_SECRET schollz/croc "$@"; } ``` You can also just paste it in the terminal for current session. On first run Docker will pull the image. `croc` via Docker will only work within the current directory and its subdirectories. ### Build from Source If you prefer, you can [install Go](https://go.dev/dl/) and build from source (requires Go 1.22+): ```bash go install github.com/schollz/croc/v10@latest ``` ### On Android There is a 3rd-party F-Droid app [available to download](https://f-droid.org/packages/com.github.howeyc.crocgui/). ## Usage To send a file, simply do: ```bash $ croc send [file(s)-or-folder] Sending 'file-or-folder' (X MB) Code is: code-phrase ``` Then, to receive the file (or folder) on another computer, run: ```bash croc code-phrase ``` The code phrase is used to establish password-authenticated key agreement ([PAKE](https://en.wikipedia.org/wiki/Password-authenticated_key_agreement)) which generates a secret key for the sender and recipient to use for end-to-end encryption. ### Customizations & Options #### Using `croc` on Linux or macOS On Linux and macOS, the sending and receiving process is slightly different to avoid [leaking the secret via the process name](https://nvd.nist.gov/vuln/detail/CVE-2023-43621). You will need to run `croc` with the secret as an environment variable. For example, to receive with the secret `***`: ```bash CROC_SECRET=*** croc ``` For single-user systems, the default behavior can be permanently enabled by running: ```bash croc --classic ``` #### Custom Code Phrase You can send with your own code phrase (must be more than 6 characters): ```bash croc send --code [code-phrase] [file(s)-or-folder] ``` #### Allow Overwriting Without Prompt To automatically overwrite files without prompting, use the `--overwrite` flag: ```bash croc --yes --overwrite
```
#### Excluding Folders
To exclude folders from being sent, use the `--exclude` flag with comma-delimited exclusions:
```bash
croc send --exclude "node_modules,.venv" [folder]
```
#### Use Pipes - stdin and stdout
You can pipe to `croc`:
```bash
cat [filename] | croc send
```
To receive the file to `stdout`, you can use:
```bash
croc --yes [code-phrase] > out
```
#### Send Text
To send URLs or short text, use:
```bash
croc send --text "hello world"
```
#### Use a Proxy
You can send files via a proxy by adding `--socks5`:
```bash
croc --socks5 "127.0.0.1:9050" send SOMEFILE
```
#### Change Encryption Curve
To choose a different elliptic curve for encryption, use the `--curve` flag:
```bash
croc --curve p521
```
#### Change Hash Algorithm
For faster hashing, use the `imohash` algorithm:
```bash
croc send --hash imohash SOMEFILE
```
#### Self-host Relay
You can run your own relay:
```bash
croc relay
```
By default, it uses TCP ports 9009-9013. You can customize the ports (e.g., `croc relay --ports 1111,1112`), but at least **2** ports are required.
To send files using your relay:
```bash
croc --relay "myrelay.example.com:9009" send [filename]
```
#### Self-host Relay with Docker
You can also run a relay with Docker:
```bash
docker run -d -p 9009-9013:9009-9013 -e CROC_PASS='YOURPASSWORD' schollz/croc
```
To send files using your custom relay:
```bash
croc --pass YOURPASSWORD --relay "myreal.example.com:9009" send [filename]
```
## Acknowledgements
`croc` has evolved through many iterations, and I am thankful for the contributions! Special thanks to:
- [@warner](https://github.com/warner) for the [idea](https://github.com/magic-wormhole/magic-wormhole)
- [@tscholl2](https://github.com/tscholl2) for the [encryption gists](https://gist.github.com/tscholl2/dc7dc15dc132ea70a98e8542fefffa28)
- [@skorokithakis](https://github.com/skorokithakis) for [proxying two connections](https://www.stavros.io/posts/proxying-two-connections-go/)
And many more!