/** PATH-like string with system dirs appended (never drops existing entries). */
export declare function augmentedPathEnv(base?: string): string;
/**
 * Locate an executable without invoking a shell or `which`.
 * Works when `/bin/sh` is missing and when PATH is incomplete.
 */
export declare function findExecutable(command: string): Promise<string | undefined>;
export declare function commandAvailable(command: string): Promise<boolean>;
/** Sync variant for version probes. */
export declare function findExecutableSync(command: string): string | undefined;