croc/README.md

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<p align="center"><code>curl https://getcroc.schollz.com | bash</code></p>

*croc* is a tool that allows any two computers to simply and securely transfer files and folders. There are many tools that can do this but AFAIK *croc* is the only tool that is easily installed and used on any platform, *and* has secure peer-to-peer transferring (through a relay), allows multiple files, *and* has the capability to resume broken transfers. 


For more information on how croc works, see [my blog post](https://schollz.com/software/croc).


## Install

Download [the latest release for your system](https://github.com/schollz/croc/releases/latest), or install a release from the command-line:

```
$ curl https://getcroc.schollz.com | bash
```


Or, you can [install Go](https://golang.org/dl/) and build from source (requires Go 1.11+): 

```
go get github.com/schollz/croc
```



## Usage 

To send a file, simply do: 

```
$ croc send FILE
```

Them to receive the file, you can just do 

```
$ croc [code-phrase]
```

### Custom code phrase

You can send with your own code phrase (must be more than 4 characters).

```
$ croc send --code [code phrase] [filename]
```

### Use locally

*croc* automatically will attempt to start a local connection on your LAN to transfer the file much faster. It uses [peer discovery](https://github.com/schollz/peerdiscovery), basically broadcasting a message on the local subnet to see if another *croc* user wants to receive the file. *croc* will utilize the first incoming connection from either the local network or the public relay and follow through with PAKE.

You can change this behavior by forcing *croc* to use only local connections (`--local`) or force to use the public relay only (`--no-local`):

```
$ croc --local/--no-local send [filename]
```

### Using pipes - stdin and stdout

You can easily use *croc* in pipes when you need to send data through stdin or get data from stdout. To send you can just use pipes:

```
$ cat [filename] | croc send
```

In this case *croc* will automatically use the stdin data and send and assign a filename like "croc-stdin-123456789". To receive to stdout at you can always just use the `-yes` and `-stdout` flags which will automatically approve the transfer and pipe it out to stdout. 

```
$ croc -yes -stdout [code phrase] > out
```

All of the other text printed to the console is going to `stderr` so it will not interfere with the message going to stdout.

### Self-host relay

The relay is needed to staple the parallel incoming and outgoing connections. The relay temporarily stores connection information and the encrypted meta information. The default uses a public relay at, `croc4.schollz.com`. You can also run your own relay, it is very easy, just run:

```
$ croc relay
```

Make sure to open up TCP ports (see `croc relay --help` for which ports to open). Relays can also be customized to which elliptic curve they will use (default is siec).

You can send files using your relay by entering `-addr` to change the relay that you are using if you want to custom host your own.

```
$ croc -addr "myrelay.example.com" send [filename]
```

### Configuration file 

You can also make some paramters static by using a configuration file. To get started with the config file just do 

```
$ croc config
```

which will generate the file that you can edit. 
Any changes you make to the configuration file will be applied *before* the command-line flags, if any.


## License

MIT

## Acknowledgements

*croc* has been through many iterations, and I am awed by all the great contributions! If you feel like contributing, in any way, by all means you can send an Issue, a PR, ask a question, or tweet me ([@yakczar](http://ctt.ec/Rq054)).

Thanks...

- ...[@warner](https://github.com/warner) for the [idea](https://github.com/warner/magic-wormhole).
- ...[@tscholl2](https://github.com/tscholl2) for the [encryption gists](https://gist.github.com/tscholl2/dc7dc15dc132ea70a98e8542fefffa28).
- ...[@skorokithakis](https://github.com/skorokithakis) for [code on proxying two connections](https://www.stavros.io/posts/proxying-two-connections-go/).
- ...for making pull requests [@Girbons](https://github.com/Girbons), [@techtide](https://github.com/techtide), [@heymatthew](https://github.com/heymatthew), [@Lunsford94](https://github.com/Lunsford94), [@lummie](https://github.com/lummie), [@jesuiscamille](https://github.com/jesuiscamille), [@threefjord](https://github.com/threefjord), [@marcossegovia](https://github.com/marcossegovia), [@csleong98](https://github.com/csleong98), [@afotescu](https://github.com/afotescu), [@callmefever](https://github.com/callmefever), [@El-JojA](https://github.com/El-JojA), [@anatolyyyyyy](https://github.com/anatolyyyyyy), [@goggle](https://github.com/goggle), [@smileboywtu](https://github.com/smileboywtu), [@nicolashardy](https://github.com/nicolashardy)!