Croc – Secure and Fast File Transfer via Terminal

Networking Software
March 25, 2025
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4 minutes read

Croc is a free and open-source program for secure and fast file transfer using the command line. It is available for Windows, macOS, Linux, Android, and iOS.

Key Features of Croc

The name “Croc” is symbolic and represents an association with a crocodile that transports things from one shore to another, just like this tool does with files.

Croc uses P2P (peer-to-peer) file transfer. If a direct P2P connection is not possible (due to NAT or firewalls), Croc automatically utilizes a relay server to bridge the connection. End-to-end encryption is applied during data transfer. There are no file size limitations.

File transfer is executed with a simple command in the command line:
croc send filename.ext
This command generates a unique code that the recipient must enter to download the file using the command:
croc code_for_download
Because of this, only a designated recipient can download the files.

It is also possible to send multiple files at once or entire folders. To send multiple files, use the following command:
croc send file1.txt file2.jpg file3.pdf
If you need to send a whole folder, enter the following command in the command line:
croc send -r folder_name

Croc automatically verifies the hash values of transferred data and detects LAN connections for faster transfers. Files are never stored on intermediary servers. Users can define their own code instead of the automatically generated one.

Once installed, Croc is ready to use immediately. All configurations are handled automatically, so there is no need to configure firewalls, port forwarding, or additional network parameters. If the connection is interrupted, Croc resumes the transfer automatically as soon as the connection is reestablished.

Practical Use of Croc

Croc is an excellent solution for fast, private, and reliable file sharing. There is no need to use external servers or cloud services. Thanks to its resume capability, it works well even on unstable internet connections. Being open-source, anyone with the necessary skills can customize it or integrate it into more complex programs.

One drawback that may deter inexperienced users is the lack of a graphical user interface. It is also important to note that both parties must have the application installed.

Its P2P technology, encryption, and automatic network problem resolution make it highly efficient for file transfers in different environments. Due to its direct file transfer between devices, the process is very fast.

Croc is available for all major desktop platforms but can also be used on Raspberry Pi and Android devices via Termux, as well as on iOS via the iSH terminal emulator. There is also a version for Android with a simple graphical interface available on the F-Droid platform, but it has not been updated recently. You can download it HERE.

Croc is primarily intended for users familiar with command-line operations, but others can use it as well. It is commonly used by developers for file sharing between different devices, teams working on joint projects with large amounts of data, and system administrators for transferring configuration and log files between servers.

Platform:
Windows, Linux, macOS, Android, and iOS