os
Operating System Facilities.
os| os.clock() | 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 format. |
| os.difftime(t2, t1) | Returns the number of seconds from time t1 to time t2. |
| os.execute(command) | This function is equivalent to the C function system. |
| os.exit(code) | Calls the C function exit, with an optional code, to terminate the
host program. |
| os.getenv(varname) | Returns the value of the process environment variable varname, or
nil if the variable is not defined. |
| os.remove(filename) | Deletes the file or directory with the given name. |
| os.rename(oldname, newname) | Renames file or directory named oldname to newname. |
| os.setlocale(locale, category) | Sets the current locale of the program. |
| os.time(table) | Returns the current time when called without arguments, or a time representing the date and time specified by the given table. |
osos.clock()
os.date(format, time)
format.
time argument is present, this is the time to be formatted
(see the os.time function for a description of this value). Otherwise,
date formats the current time.
If format starts with '!', then the date is formatted in Coordinated
Universal Time. After this optional character, if format is the string
"*t", then date returns a table with the following fields:
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). If format is not "*t", then date returns the date as a string,
formatted according to the same rules as the C function strftime.
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.date("%c")).
format
:
time
:
os.difftime(t2, t1)
t1 to time t2.
t2-t1.
t2
:
t1
:
os.execute(command)
system.
command to be executed by an operating system shell. It returns a status
code, which is system-dependent. If command is absent, then it returns
nonzero if a shell is available and zero otherwise.
command
:
os.exit(code)
exit, with an optional code, to terminate the
host program.
code is the success code.
code
:
os.getenv(varname)
varname, or
nil if the variable is not defined.
varname
:
os.remove(filename)
filename
:
os.rename(oldname, newname)
oldname to newname.
oldname
:
newname
:
os.setlocale(locale, category)
locale is a string specifying
a locale; category is an optional string describing which category to
change: "all", "collate", "ctype", "monetary", "numeric", or
"time"; the default category is "all". The function returns the name
of the new locale, or nil if the request cannot be honored.
If locale is the empty string, the current locale is set to an
implementation-defined native locale. If locale is the string "C",
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.
locale
:
category
:
os.time(table)
year, month, and day, and may have fields hour,
min, sec, and isdst (for a description of these fields, see the
os.date function).
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 date and difftime.
table
: