On OS X, where date
does not support the %N
flag, I recommend installing coreutils
using Homebrew. This will give you access to a command called gdate
that will behave as date
does on Linux systems.
brew install coreutils
For a more "native" experience, you can always add this to your .bash_aliases
:
alias date='gdate'
Then execute
$ date +%s%N
Nano is 10-9 and milli 10-3. Hence, we can use the three first characters of nanoseconds to get the milliseconds:
date +%s%3N
From man date
:
%N nanoseconds (000000000..999999999)
%s seconds since 1970-01-01 00:00:00 UTC
Source: Server Fault's How do I get the current Unix time in milliseconds in Bash?.
A Python script like this:
import time
cur_time = int(time.time()*1000)
To show date with time and time-zone
date +"%d-%m-%Y %T.%N %Z"
Output : 22-04-2020 18:01:35.970289239 IST
Perl can be used for this, even on exotic platforms like AIX. Example:
#!/usr/bin/perl -w
use strict;
use Time::HiRes qw(gettimeofday);
my ($t_sec, $usec) = gettimeofday ();
my $msec= int ($usec/1000);
my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
localtime ($t_sec);
printf "%04d-%02d-%02d %02d:%02d:%02d %03d\n",
1900+$year, 1+$mon, $mday, $hour, $min, $sec, $msec;
date +"%T.%N"
returns the current time with nanoseconds.
06:46:41.431857000
date +"%T.%6N"
returns the current time with nanoseconds rounded to the first 6 digits, which is microseconds.
06:47:07.183172
date +"%T.%3N"
returns the current time with nanoseconds rounded to the first 3 digits, which is milliseconds.
06:47:42.773
In general, every field of the date
command's format can be given an optional field width.
When you use GNU AWK since version 4.1, you can load the time library and do:
$ awk '@load "time"; BEGIN{printf "%.6f", gettimeofday()}'
This will print the current time in seconds since 1970-01-01T00:00:00 in sub second accuracy.
the_time = gettimeofday()
Return the time in seconds that has elapsed since 1970-01-01 UTC as a floating-point value. If the time is unavailable on this platform, return-1
and setERRNO
. The returned time should have sub-second precision, but the actual precision may vary based on the platform. If the standard Cgettimeofday()
system call is available on this platform, then it simply returns the value. Otherwise, if on MS-Windows, it tries to useGetSystemTimeAsFileTime()
.source: GNU awk manual
On Linux systems, the standard C function getimeofday()
returns the time in microsecond accuracy.
I just wanted to add to Alper's answer what I had to do to get this stuff working:
On Mac, you'll need brew install coreutils
, so we can use gdate
. Otherwise on Linux, it's just date
. And this function will help you time commands without having to create temporary files or anything:
function timeit() {
start=`gdate +%s%N`
bash -c $1
end=`gdate +%s%N`
runtime=$(((end-start)/1000000000.0))
echo " seconds"
}
And you can use it with a string:
timeit 'tsc --noEmit'
Here is a somehow portable hack for Linux for getting time in milliseconds:
#!/bin/sh
read up rest </proc/uptime; t1="${up%.*}${up#*.}"
sleep 3 # your command
read up rest </proc/uptime; t2="${up%.*}${up#*.}"
millisec=$(( 10*(t2-t1) ))
echo $millisec
The output is:
3010
This is a very cheap operation, which works with shell internals and procfs.
The other answers are probably sufficient in most cases but I thought I'd add my two cents as I ran into a problem on a BusyBox system.
The system in question did not support the %N
format option and doesn't have no Python or Perl interpreter.
After much head scratching, we (thanks Dave!) came up with this:
adjtimex | awk '/(time.tv_sec|time.tv_usec):/ { printf("%06d", $2) }'
It extracts the seconds and microseconds from the output of adjtimex
(normally used to set options for the system clock) and prints them without new lines (so they get glued together). Note that the microseconds field has to be pre-padded with zeros, but this doesn't affect the seconds field which is longer than six digits anyway. From this it should be trivial to convert microseconds to milliseconds.
If you need a trailing new line (maybe because it looks better) then try
adjtimex | awk '/(time.tv_sec|time.tv_usec):/ { printf("%06d", $2) }' && printf "\n"
Also note that this requires adjtimex
and awk
to be available. If not then with BusyBox you can point to them locally with:
ln -s /bin/busybox ./adjtimex
ln -s /bin/busybox ./awk
And then call the above as
./adjtimex | ./awk '/(time.tv_sec|time.tv_usec):/ { printf("%06d", $2) }'
Or of course you could put them in your PATH
EDIT:
The above worked on my BusyBox device. On Ubuntu I tried the same thing and realised that adjtimex
has different versions. On Ubuntu this worked to output the time in seconds with decimal places to microseconds (including a trailing new line)
sudo apt-get install adjtimex
adjtimex -p | awk '/raw time:/ { print $6 }'
I wouldn't do this on Ubuntu though. I would use date +%s%N
date
command didnt provide milli seconds on OS X, so used an alias from python
millis(){ python -c "import time; print(int(time.time()*1000))"; }
OR
alias millis='python -c "import time; print(int(time.time()*1000))"'
EDIT: following the comment from @CharlesDuffy. Forking any child process takes extra time.
$ time date +%s%N
1597103627N
date +%s%N 0.00s user 0.00s system 63% cpu 0.006 total
Python is still improving it's VM start time, and it is not as fast as ahead-of-time compiled code (such as date
).
On my machine, it took about 30ms - 60ms (that is 5x-10x of 6ms taken by date
)
$ time python -c "import time; print(int(time.time()*1000))"
1597103899460
python -c "import time; print(int(time.time()*1000))" 0.03s user 0.01s system 83% cpu 0.053 total
I figured awk
is lightweight than python
, so awk
takes in the range of 6ms to 12ms (i.e. 1x to 2x of date):
$ time awk '@load "time"; BEGIN{print int(1000 * gettimeofday())}'
1597103729525
awk '@load "time"; BEGIN{print int(1000 * gettimeofday())}' 0.00s user 0.00s system 74% cpu 0.010 total
Source: Stackoverflow.com