os.setlocale (locale [, category]) Sets the current locale of the program. locale is a system-dependent string specifying a locale; category is an optional

os.getenv (varname) Returns the value of the process environment variable varname, or nil if the variable is not defined.

os.tmpname () Returns a string with a file name that can be used for a temporary file. The file must be explicitly opened before its use and explicitly removed when no longer

os.exit ([code [, close]]) Calls the ISO C function exit to terminate the host program. If code is true, the returned status is EXIT_SUCCESS;

os.time ([table]) Returns the current time when called without arguments, or a time representing the local date and time specified by the given table. This table must have fields

os.rename (oldname, newname) Renames the file or directory named oldname to newname. If this function fails, it returns nil, plus a string describing

os.execute ([command]) This function is equivalent to the ISO C function system. It passes command to be executed by an operating system shell. Its first

os.remove (filename) Deletes the file (or empty directory, on POSIX systems) with the given name. If this function fails, it returns nil, plus a string describing the error

os.date ([format [, time]]) Returns a string or a table containing date and time, formatted according to the given string format. If the time

os.clock () Returns an approximation of the amount in seconds of CPU time used by the program.