os.WEXITSTATUS(status) If WIFEXITED(status) is true, return the integer parameter to the exit(2) system call. Otherwise, the return value is meaningless. Availability: Unix.

os.WCOREDUMP(status) Return True if a core dump was generated for the process, otherwise return False. Availability: Unix.

os.walk(top, topdown=True, onerror=None, followlinks=False) Generate the file names in a directory tree by walking the tree either top-down or bottom-up. For each directory in the tree rooted at directory top (including top itself), it yields a 3-tuple (dirpath, dirnames, filenames). dirpath is a string, the path to the directory. dirnames is a list of the names of the subdirectories in dirpath (excluding '.' and '..'). filenames is a list of the names of the non-directory files in dirpath.

os.waitpid(pid, options) The details of this function differ on Unix and Windows. On Unix: Wait for completion of a child process given by process id pid, and return a tuple containing its process id and exit status indication (encoded as for wait()). The semantics of the call are affected by the value of the integer options, which should be 0 for normal operation. If pid is greater than 0, waitpid() requests status information for that specific process. If pid is 0, the request is for the s

os.waitid(idtype, id, options) Wait for the completion of one or more child processes. idtype can be P_PID, P_PGID or P_ALL. id specifies the pid to wait on. options is constructed from the ORing of one or more of WEXITED, WSTOPPED or WCONTINUED and additionally may be ORed with WNOHANG or WNOWAIT. The return value is an object representing the data contained in the siginfo_t structure, namely: si_pid, si_uid, si_signo, si_status, si_code or None if WNOHANG is specified and there are no chil

os.wait4(pid, options) Similar to waitpid(), except a 3-element tuple, containing the child’s process id, exit status indication, and resource usage information is returned. Refer to resource.getrusage() for details on resource usage information. The arguments to wait4() are the same as those provided to waitpid(). Availability: Unix.

os.wait3(options) Similar to waitpid(), except no process id argument is given and a 3-element tuple containing the child’s process id, exit status indication, and resource usage information is returned. Refer to resource.getrusage() for details on resource usage information. The option argument is the same as that provided to waitpid() and wait4(). Availability: Unix.

os.wait() Wait for completion of a child process, and return a tuple containing its pid and exit status indication: a 16-bit number, whose low byte is the signal number that killed the process, and whose high byte is the exit status (if the signal number is zero); the high bit of the low byte is set if a core file was produced. Availability: Unix.

os.utime(path, times=None, *, [ns, ]dir_fd=None, follow_symlinks=True) Set the access and modified times of the file specified by path. utime() takes two optional parameters, times and ns. These specify the times set on path and are used as follows: If ns is specified, it must be a 2-tuple of the form (atime_ns, mtime_ns) where each member is an int expressing nanoseconds. If times is not None, it must be a 2-tuple of the form (atime, mtime) where each member is an int or float expressing se

os.urandom(n) Return a string of n random bytes suitable for cryptographic use. This function returns random bytes from an OS-specific randomness source. The returned data should be unpredictable enough for cryptographic applications, though its exact quality depends on the OS implementation. On Linux, getrandom() syscall is used if available and the urandom entropy pool is initialized (getrandom() does not block). On a Unix-like system this will query /dev/urandom. On Windows, it will use C