System commands

Hook scripts can run programs with system::command. First, register the script as a hook in cargo-generate.toml:

[hooks]
post = ["post-script.rhai"]

Then call the program from post-script.rhai, passing its arguments in an array:

system::command("cargo", ["fmt"]);

let rustc_version = system::command("rustc", ["--version"]);
print(`Generated with ${rustc_version}`);

Commands run in the template’s working directory through sh on Unix and cmd on Windows, so available programs and shell syntax can vary by platform. On success, system::command returns trimmed standard output, or () if the command produced no output. A command that cannot start or exits unsuccessfully stops template generation with an error.

By default, cargo-generate shows the requested command and asks the user to approve it. To run commands without confirmation, the user must opt in:

cargo generate --git https://github.com/example/template.git --allow-commands

The --silent option cannot run a command hook unless --allow-commands is also set. A template cannot enable this permission for itself.

Security warning: --allow-commands lets a template execute arbitrary shell commands with your user account’s permissions and without further confirmation. Those commands can access secrets, modify files outside the generated project, or communicate over the network. Arguments are joined into shell command text without automatic quoting or escaping, so template authors must not insert untrusted values. Only enable commands for templates you trust after reviewing their hook scripts and imported modules.

See the system module reference for the complete function signature and more examples.