os

OS routines for NT or Posix depending on what system we’re on.

This exports:
  • all functions from posix, nt, os2, or ce, e.g. unlink, stat, etc.
  • os.path is one of the modules posixpath, or ntpath
  • os.name is ‘posix’, ‘nt’, ‘os2’, ‘ce’ or ‘riscos’
  • os.curdir is a string representing the current directory (‘.’ or ‘:’)
  • os.pardir is a string representing the parent directory (‘..’ or ‘::’)
  • os.sep is the (or a most common) pathname separator (‘/’ or ‘:’ or ‘\’)
  • os.extsep is the extension separator (‘.’ or ‘/’)
  • os.altsep is the alternate pathname separator (None or ‘/’)
  • os.pathsep is the component separator used in $PATH etc
  • os.linesep is the line separator in text files (‘r’ or ‘n’ or ‘rn’)
  • os.defpath is the default search path for executables
  • os.devnull is the file path of the null device (‘/dev/null’, etc.)

Programs that import and use ‘os’ stand a better chance of being portable between different platforms. Of course, they must then only use functions that are defined by all platforms (e.g., unlink and opendir), and leave all pathname manipulation to os.path (e.g., split and join).

Functions

WCOREDUMP((status) -> bool) Return True if the process returning ‘status’ was dumped to a core file.
WEXITSTATUS((status) -> integer) Return the process return code from ‘status’.
WIFCONTINUED((status) -> bool) Return True if the process returning ‘status’ was continued from a job control stop.
WIFEXITED((status) -> bool) Return true if the process returning ‘status’ exited using the exit() system call.
WIFSIGNALED((status) -> bool) Return True if the process returning ‘status’ was terminated by a signal.
WIFSTOPPED((status) -> bool) Return True if the process returning ‘status’ was stopped.
WSTOPSIG((status) -> integer) Return the signal that stopped the process that provided the ‘status’ value.
WTERMSIG((status) -> integer) Return the signal that terminated the process that provided the ‘status’ value.
abort(() -> does not return!) Abort the interpreter immediately.
access((path, mode) -> True if granted, ...) Use the real uid/gid to test for access to a path.
chdir(path) Change the current working directory to the specified path.
chmod(path, mode) Change the access permissions of a file.
chown(path, uid, gid) Change the owner and group id of path to the numeric uid and gid.
chroot(path) Change root directory to path.
close(fd) Close a file descriptor (for low level IO).
closerange(fd_low, fd_high) Closes all file descriptors in [fd_low, fd_high), ignoring errors.
confstr((name) -> string) Return a string-valued system configuration variable.
ctermid(() -> string) Return the name of the controlling terminal for this process.
dup((fd) -> fd2) Return a duplicate of a file descriptor.
dup2(old_fd, new_fd) Duplicate file descriptor.
execl(file, *args) Execute the executable file with argument list args, replacing the current process.
execle(file, *args, env) Execute the executable file with argument list args and environment env, replacing the current process.
execlp(file, *args) Execute the executable file (which is searched for along $PATH) with argument list args, replacing the current process.
execlpe(file, *args, env) Execute the executable file (which is searched for along $PATH) with argument list args and environment env, replacing the current process.
execv(path, args) Execute an executable path with arguments, replacing current process.
execve(path, args, env) Execute a path with arguments and environment, replacing current process.
execvp(file, args) Execute the executable file (which is searched for along $PATH) with argument list args, replacing the current process.
execvpe(file, args, env) Execute the executable file (which is searched for along $PATH) with argument list args and environment env , replacing the current process.
fchdir(fildes) Change to the directory of the given file descriptor.
fchmod(fd, mode) Change the access permissions of the file given by file descriptor fd.
fchown(fd, uid, gid) Change the owner and group id of the file given by file descriptor fd to the numeric uid and gid.
fdatasync(fildes) force write of file with filedescriptor to disk.
fdopen((fd [[, mode]) Return an open file object connected to a file descriptor.
fork(() -> pid) Fork a child process.
forkpty() -> (pid, master_fd) Fork a new process with a new pseudo-terminal as controlling tty.
fpathconf((fd, name) -> integer) Return the configuration limit name for the file descriptor fd.
fstat((fd) -> stat result) Like stat(), but for an open file descriptor.
fstatvfs((fd) -> statvfs result) Perform an fstatvfs system call on the given fd.
fsync(fildes) force write of file with filedescriptor to disk.
ftruncate(fd, length) Truncate a file to a specified length.
getcwd(() -> path) Return a string representing the current working directory.
getcwdu(() -> path) Return a unicode string representing the current working directory.
getegid(() -> egid) Return the current process’s effective group id.
getenv(key[, default]) Get an environment variable, return None if it doesn’t exist.
geteuid(() -> euid) Return the current process’s effective user id.
getgid(() -> gid) Return the current process’s group id.
getgroups(() -> list of group IDs) Return list of supplemental group IDs for the process.
getloadavg() -> (float, float, float) Return the number of processes in the system run queue averaged over
getlogin(() -> string) Return the actual login name.
getpgid((pid) -> pgid) Call the system call getpgid().
getpgrp(() -> pgrp) Return the current process group id.
getpid(() -> pid) Return the current process id
getppid(() -> ppid) Return the parent’s process id.
getresgid() -> (rgid, egid, sgid) Get tuple of the current process’s real, effective, and saved group ids.
getresuid() -> (ruid, euid, suid) Get tuple of the current process’s real, effective, and saved user ids.
getsid((pid) -> sid) Call the system call getsid().
getuid(() -> uid) Return the current process’s user id.
initgroups((username, gid) -> None) Call the system initgroups() to initialize the group access list with all of the groups of which the specified username is a member, plus the specified group id.
isatty((fd) -> bool) Return True if the file descriptor ‘fd’ is an open file descriptor connected to the slave end of a terminal.
kill(pid, sig) Kill a process with a signal.
killpg(pgid, sig) Kill a process group with a signal.
lchown(path, uid, gid) Change the owner and group id of path to the numeric uid and gid.
link(src, dst) Create a hard link to a file.
listdir((path) -> list_of_strings) Return a list containing the names of the entries in the directory.
lseek((fd, pos, how) -> newpos) Set the current position of a file descriptor.
lstat((path) -> stat result) Like stat(path), but do not follow symbolic links.
major((device) -> major number) Extracts a device major number from a raw device number.
makedev((major, minor) -> device number) Composes a raw device number from the major and minor device numbers.
makedirs(path [[, mode]) Super-mkdir; create a leaf directory and all intermediate ones.
minor((device) -> minor number) Extracts a device minor number from a raw device number.
mkdir(path [[, mode]) Create a directory.
mkfifo(filename [[, mode]) Create a FIFO (a POSIX named pipe).
mknod(filename [[, mode]) Create a filesystem node (file, device special file or named pipe) named filename.
nice((inc) -> new_priority) Decrease the priority of process by inc and return the new priority.
open((filename, flag [[, mode]) Open a file (for low level IO).
openpty() -> (master_fd, slave_fd) Open a pseudo-terminal, returning open fd’s for both master and slave end.
pathconf((path, name) -> integer) Return the configuration limit name for the file or directory path.
pipe() -> (read_end, write_end) Create a pipe.
popen((command [[, mode]) Open a pipe to/from a command returning a file object.
popen2(cmd[, mode, bufsize]) Execute the shell command ‘cmd’ in a sub-process.
popen3(cmd[, mode, bufsize]) Execute the shell command ‘cmd’ in a sub-process.
popen4(cmd[, mode, bufsize]) Execute the shell command ‘cmd’ in a sub-process.
putenv(key, value) Change or add an environment variable.
read((fd, buffersize) -> string) Read a file descriptor.
readlink((path) -> path) Return a string representing the path to which the symbolic link points.
remove(path) Remove a file (same as unlink(path)).
removedirs(path) Super-rmdir; remove a leaf directory and all empty intermediate ones.
rename(old, new) Rename a file or directory.
renames(old, new) Super-rename; create directories as necessary and delete any left empty.
rmdir(path) Remove a directory.
setegid(gid) Set the current process’s effective group id.
seteuid(uid) Set the current process’s effective user id.
setgid(gid) Set the current process’s group id.
setgroups(list) Set the groups of the current process to list.
setpgid(pid, pgrp) Call the system call setpgid().
setpgrp() Make this process the process group leader.
setregid(rgid, egid) Set the current process’s real and effective group ids.
setresgid(rgid, egid, sgid) Set the current process’s real, effective, and saved group ids.
setresuid(ruid, euid, suid) Set the current process’s real, effective, and saved user ids.
setreuid(ruid, euid) Set the current process’s real and effective user ids.
setsid() Call the system call setsid().
setuid(uid) Set the current process’s user id.
spawnl((mode, file, *args) -> integer) Execute file with arguments from args in a subprocess.
spawnle((mode, file, *args, env) -> integer) Execute file with arguments from args in a subprocess with the supplied environment.
spawnlp((mode, file, *args) -> integer) Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment.
spawnlpe((mode, file, *args, env) -> integer) Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment.
spawnv((mode, file, args) -> integer) Execute file with arguments from args in a subprocess.
spawnve((mode, file, args, env) -> integer) Execute file with arguments from args in a subprocess with the specified environment.
spawnvp((mode, file, args) -> integer) Execute file (which is looked for along $PATH) with arguments from args in a subprocess.
spawnvpe((mode, file, args, env) -> integer) Execute file (which is looked for along $PATH) with arguments from args in a subprocess with the supplied environment.
stat((path) -> stat result) Perform a stat system call on the given path.
stat_float_times(([newval]) -> oldval) Determine whether os.[lf]stat represents time stamps as float objects.
statvfs((path) -> statvfs result) Perform a statvfs system call on the given path.
strerror((code) -> string) Translate an error code to a message string.
symlink(src, dst) Create a symbolic link pointing to src named dst.
sysconf((name) -> integer) Return an integer-valued system configuration variable.
system((command) -> exit_status) Execute the command (a string) in a subshell.
tcgetpgrp((fd) -> pgid) Return the process group associated with the terminal given by a fd.
tcsetpgrp(fd, pgid) Set the process group associated with the terminal given by a fd.
tempnam(([dir[, prefix]]) -> string) Return a unique name for a temporary file.
times() -> (utime, stime, cutime, cstime, ...) Return a tuple of floating point numbers indicating process times.
tmpfile(() -> file object) Create a temporary file with no directory entries.
tmpnam(() -> string) Return a unique name for a temporary file.
ttyname((fd) -> string) Return the name of the terminal device connected to ‘fd’.
umask((new_mask) -> old_mask) Set the current numeric umask and return the previous umask.
uname() -> (sysname, nodename, release, ...) Return a tuple identifying the current operating system.
unlink(path) Remove a file (same as remove(path)).
unsetenv(key) Delete an environment variable.
urandom((n) -> str) Return n random bytes suitable for cryptographic use.
utime(path, (atime, mtime)) utime(path, None) Set the access and modified time of the file to the given values.
wait() -> (pid, status) Wait for completion of a child process.
wait3(options) -> (pid, status, rusage) Wait for completion of a child process.
wait4(pid, options) -> (pid, status, rusage) Wait for completion of a given child process.
waitpid(pid, options) -> (pid, status) Wait for completion of a given child process.
walk(top[, topdown, onerror, followlinks]) Directory tree generator.
write((fd, string) -> byteswritten) Write a string to a file descriptor.

Classes

stat_result stat_result: Result from stat or lstat.
statvfs_result statvfs_result: Result from statvfs or fstatvfs.

Exceptions

error alias of OSError