6.1.1 Process Parameters

These functions and data items provide information and operate on the current process and user.

chdir (path)

Change the current working directory to path. Availability: Macintosh, Unix, Windows.

environ

A mapping representing the string environment. For example, environ['HOME'] is the pathname of your home directory, equivalent to getenv("HOME") in C.

If the platform supports the putenv() function, this mapping may be used to modify the environment as well as query the environment. putenv() will be called automatically when the mapping is modified.

If putenv() is not provided, this mapping may be passed to the appropriate process-creation functions to cause child processes to use a modified environment.

getcwd ()

Return a string representing the current working directory. Availability: Macintosh, Unix, Windows.

getegid ()

Return the current process' effective group id. Availability: Unix.

geteuid ()

Return the current process' effective user id. Availability: Unix.

getgid ()

Return the current process' group id. Availability: Unix.

getpgrp ()

Return the current process group id. Availability: Unix.

getpid ()

Return the current process id. Availability: Unix, Windows.

getppid ()

Return the parent's process id. Availability: Unix.

getuid ()

Return the current process' user id. Availability: Unix.

putenv (varname, value)

Set the environment variable named varname to the string value. Such changes to the environment affect subprocesses started with os.system(), popen() or fork() and execv(). Availability: most flavors of Unix, Windows.

When putenv() is supported, assignments to items in os.environ are automatically translated into corresponding calls to putenv(); however, calls to putenv() don't update os.environ, so it is actually preferable to assign to items of os.environ.

setgid (gid)

Set the current process' group id. Availability: Unix.

setpgrp ()

Calls the system call setpgrp() or setpgrp(0, 0) depending on which version is implemented (if any). See the Unix manual for the semantics. Availability: Unix.

setpgid (pid, pgrp)

Calls the system call setpgid(). See the Unix manual for the semantics. Availability: Unix.

setsid ()

Calls the system call setsid(). See the Unix manual for the semantics. Availability: Unix.

setuid (uid)

Set the current process' user id. Availability: Unix.

strerror (code)

Return the error message corresponding to the error code in code. Availability: Unix, Windows.

umask (mask)

Set the current numeric umask and returns the previous umask. Availability: Unix, Windows.

uname ()

Return a 5-tuple containing information identifying the current operating system. The tuple contains 5 strings: (sysname, nodename, release, version, machine). Some systems truncate the nodename to 8 characters or to the leading component; a better way to get the hostname is socket.gethostname() or even socket.gethostbyaddr(socket.gethostname()). Availability: recent flavors of Unix.