extern int issue_command (const char *cmd, char *argv[], const char *pipe, int rc_exit_on_error_flag);
extern void list_builtin_commands (void);
extern int display_builtin_command (const char *cmd);
extern int issue_command (const char *cmd, char *argv[], const char *pipe, int rc_exit_on_error_flag);
extern void list_builtin_commands (void);
extern int display_builtin_command (const char *cmd);