Is there any file I can read in unix which contains the time

Question

Is there any file in unix based system which I can read, to get the same value that time() in php would return?

Answer 1

Unlike my other answer reading metadata, grepping through /proc for "sec" I indeed found a file containing the current system time:

/proc/timer_list contains two values: the uptime in nsec (now at...) and a little further down the time the system was started, also in nsec (.offset). If you add them and divide through 10^9 you've got the current time.

Timer List Version: v0.6
HRTIMER_MAX_CLOCK_BASES: 2
now at 2089173850911347 nsecs

cpu: 0
 clock 0:
  .base:       0000000000000000
  .index:      0
  .resolution: 1 nsecs
  .get_time:   ktime_get_real
  .offset:     1316955129915578545 nsecs

EDIT: And another one: /sys/devices/pnp0/00:05/rtc/rtc0/since_epoch seems to contain the real unix timestamp, no offset or such. But I'm not sure about what this file is really about, just found it grepping.

If you've also got some terminal access for development you can try yourself:

grep 131904 `find /sys 2>/dev/null` 2>/dev/null

to find files containing the first digits of the unix timestamp (replace if using it later) in /sys you've got access to.

Answer 2

• On my system, /proc/cpuinfo's {a|c|m}time is equal to the current system time.
• Maybe you can just execute date and read from its output?

Answer 3

PHP's time() function returns seconds since the Unix epoch. You can format it as a date and/or time any way you want using other PHP functions.

Unix's date command (at least the GNU version) can do the same

# date "+%s"
1319042692

So you can easily create a file containing that number, as needed (e.g. using PHP's system() function)

Or just read it directly

$secs_since_epoch = system('date "+%s"', $return_value);

I can't think of a sensible use case for what you ask though.