Command Helpers

Functions for executing shell commands with different return types and behaviors.

Overview

These functions have PREFIX and BUILD_DIR environment variables set automatically. The shell_in() variants run commands in a specific directory.

shell

Run a shell command. Throws an error if the command fails (non-zero exit).

rust|

shell("make -j" + NPROC);
shell("install -Dm755 myapp " + join_path(PREFIX, "bin/myapp"));

shell_in

Run a shell command in a specific directory. This is the recommended way to run commands in a source directory instead of changing directories.

rust|

// Run configure and make in the source directory
shell_in(ctx.source_dir, "./configure --prefix=" + PREFIX);
shell_in(ctx.source_dir, "make -j" + NPROC);
shell_in(ctx.source_dir, "make install");

shell_output

Run a command and return its stdout. Throws if the command fails.

rust|

let version = shell_output("git describe --tags");
let arch = trim(shell_output("uname -m"));
let cpus = trim(shell_output("nproc"));

shell_output_in

Run a command in a specific directory and return its stdout.

rust|

let version = shell_output_in(ctx.source_dir, "git describe --tags");

shell_status

Run a command and return its exit code. Does not throw on non-zero exit.

rust|

let status = shell_status("command -v clang");
if status == 0 {
    set_env("CC", "clang");
}

// Check if a command exists
if shell_status("which rustc") == 0 {
    log("Rust is installed");
}

shell_status_in

Run a command in a specific directory and return its exit code.

rust|

let status = shell_status_in(ctx.source_dir, "test -f Makefile");
if status != 0 {
    shell_in(ctx.source_dir, "./configure");
}

exec

Execute a command with an array of arguments (no shell interpretation). Returns the exit code. Useful when arguments contain special characters.

rust|

let code = exec("git", ["clone", "--depth", "1", url]);
let code = exec("cp", ["-r", src, dest]);

exec_output

Execute a command with array arguments and return its stdout. Throws if exit code is non-zero.

rust|

let output = exec_output("rustc", ["--version"]);
let files = exec_output("find", [src, "-name", "*.c"]);