croc

Securely transfer files or folders

TLDR

Send a file or directory

$ croc send [path/to/file_or_directory]

Send a file or directory with a specific passphrase

$ croc send [[-c|--code]] [passphrase] [path/to/file_or_directory]

Receive a file or directory on receiving machine

$ croc [passphrase]

Send and connect over a custom relay

$ croc --relay [ip_to_relay] send [path/to/file_or_directory]

Receive and connect over a custom relay

$ croc --relay [ip_to_relay] [passphrase]

Host a croc relay on the default ports

$ croc relay

Display parameters and options for a croc command

$ croc [send|relay] --help

SYNOPSIS

croc send|recv [options] [files|code]

--code Use custom 4-32 char code instead of generated one --pass Protect transfer with optional password --local Use localhost relay (for LAN) --usb Send code via USB instead of stdout --overdrive Maximize transfer speed (less secure) --socks Use SOCKS5 proxy for relay connection --port Relay port (default 9253) --stdout Send to stdout instead of file (recv only) --hash Display SHA256 hash after transfer --progress Show transfer progress bar --quiet Suppress non-error messages --debug Enable debug logging --help Show help --version Show version info


        DESCRIPTION
        
          croc is a command-line tool for securely sending files, folders, or archives between computers over the internet.

It eliminates the need for port forwarding or VPNs by using a public relay server for initial key exchange via Curve25519, Noise protocol, and ChaCha20-Poly1305 encryption for end-to-end security.

Usage is simple: on the sender side, run croc send file.txt to generate a unique code (e.g., croc-4f9b3d); share this code with the receiver, who runs croc 4f9b3d (or croc recv 4f9b3d). Transfers resume if interrupted and support passwords for protection.

Features include progress bars, resumable transfers, compression, stdout piping, USB code sharing, and overdrive mode for maximum speed. Works on Linux, macOS, Windows, and supports IPv6.
        
        CAVEATS
        
          Requires croc installed on both endpoints and internet access for relay (unless --local). Transfers limited by relay bandwidth; large files may take time. Not for production without trusted relay.
        
        INSTALLATION
        
          Download binaries from GitHub releases or install via go install github.com/schollz/croc/cmd/croc@latest or package managers like brew (macOS), snap.
        
        EXAMPLE
        
          Sender: croc send largefile.zip
Receiver: croc abc123
        
        HISTORY
        
          Developed by Jack O'Connor (@schollz) starting 2019 as open-source Go project on GitHub (github.com/schollz/croc). Reached v1.0 in 2020 with major features; actively maintained with 20k+ stars.
        
        SEE ALSO
        
          scp(1), rsync(1), wormhole(1)