-int run_command_v_opt(int argc, const char **argv, int opt);
-int run_command_v(int argc, const char **argv);
-int run_command(const char *cmd, ...);
+#define RUN_COMMAND_STDOUT_TO_STDERR 4
+int run_command_v_opt(const char **argv, int opt);
+int run_command_v_opt_cd(const char **argv, int opt, const char *dir);
+
+/*
+ * env (the environment) is to be formatted like environ: "VAR=VALUE".
+ * To unset an environment variable use just "VAR".
+ */
+int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);