Returns an approximation of the amount in seconds of CPU time used by the program.
os.date ([format [, time]])
Returns a string or a table containing date and time, formatted
according to the given string
time argument is present, this is the time to be formatted
os.time function for a description of this value).
date formats the current time.
format starts with ‘
!’, then the date is formatted in
Coordinated Universal Time. After this optional character, if
format is the string “
date returns a table with the
year (four digits) month (1--12) day (1--31) hour (0--23) min (0--59) sec (0--61) wday (weekday, Sunday is 1) yday (day of the year) isdst (daylight saving flag, a boolean)
format is not “
date returns the date as a string,
formatted according to the same rules as the function
When called without arguments,
date returns a reasonable date and
time representation that depends on the host system and on the current
locale (that is,
os.date() is equivalent to
os.difftime (t2, t1)
Returns the number of seconds from time
t1 to time
t2. In POSIX, Windows, and some other systems, this
value is exactly
This function is equivalent to the function
command to be executed by an operating system shell. It
returns a status code, which is system-dependent. If
absent, then it returns nonzero if a shell is available and zero
Calls the function
exit, with an optional
code, to terminate the
host program. The default value for
code is the success code.
Returns the value of the process environment variable
nil if the variable is not defined.
Deletes the file or directory with the given name. Directories must
be empty to be removed. If this function fails, it returns
plus a string describing the error.
os.rename (oldname, newname)
Renames file or directory named
newname. If this
function fails, it returns
nil, plus a string describing the
os.setlocale (locale [, category])
Sets the current locale of the program.
localeis a string specifying a locale;
categoryis an optional string describing which category to change:
"time"; the default category is
The function returns the name of the new locale, or
nil if the
request cannot be honored.
locale is the empty string,
the current locale is set to an implementation-defined native locale.
locale is the string “
the current locale is set to the standard C locale.
When called with
nil as the first argument, this function only
returns the name of the current locale for the given category.
Returns the current time when called without arguments, or a time
representing the date and time specified by the given table. This
table must have fields
day, and may have
isdst (for a description of
these fields, see the
The returned value is a number, whose meaning depends on your system.
In POSIX, Windows, and some other systems, this number counts the
number of seconds since some given start time (the “epoch”). In other
systems, the meaning is not specified, and the number returned by
time can be used only as an argument to
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 needed.
On some systems (POSIX), this function also creates a file with that name, to avoid security risks. (Someone else might create the file with wrong permissions in the time between getting the name and creating the file.) You still have to open the file to use it and to remove it (even if you do not use it).
When possible, you may prefer to use
automatically removes the file when the program ends.
This document is from Lua version 5.1.5. Copyright (c) 2006-2012 Lua.org, PUC-Rio. Freely available under the terms of the Lua license.