Working with ping localhost in Batch - batch-file

Question

We use ping localhost -n 2 >nul to delay its following executions.
We can change 2 to the number of seconds needed.
How can I control this in a much broader way? I tried using 1.5 instead of 2 and it didn't work.
Is there any code by which we can change the unit of time?
EDIT: Instead of ping localhost -n 2 >nul. I'm using TIMEOUT 1 >nul.

Answer 1

The command timeout is the best choice for waiting a specific time in a batch file which is designed for execution on Windows 7 and later versions of Windows. It supports breaking the timeout by the user with any key except /NOBREAK is specified as parameter. And it shows a nice message with a seconds countdown for the user informing also the user how to break the timeout. But it supports only timeout values in seconds, not in milliseconds.
The command sleep could be also used on Windows XP and later versions of Windows when having access to Windows 2003 resource kit and this small executable is copied to all computers running the batch file. But this executable is deprecated because of being replaced by TIMEOUT and by default not installed on any Windows computer.
But a good choice for all Windows is using the command ping for pinging the loopback adapter or a not reachable IP address with using appropriate values of the options -n and -w for the delay.
The IP address of the loopback adapter of local machine is 127.0.0.1, see Wikipedia articles about Reserved IP addresses. localhost is just an RFC defined alias for 127.0.0.1 defined on Windows XP and former Windows versions in file %SystemRoot%\system32\drivers\etc\hosts and is defined built-in on Windows Vista and later Windows versions.
The first ping of 127.0.0.1 is always immediately successful. Therefore using command PING with -n 1 as option gives just a delay of approximately a millisecond in total.
For that reason using PING as delay on pinging 127.0.0.1requires a value greater 1 for option -n ... number of echo requests to send. After a successful request PING waits about 1 second before making the next request.
So for a delay of 5 seconds the following command line is necessary with 6 echo requests:
%SystemRoot%\System32\ping.exe 127.0.0.1 -n 6 >nul
Note 1: Windows is not a real-time operating system and for that reason the time is not 100% accurate, but should be good enough for a batch file.
The option -w defines in milliseconds how long ping (Microsoft documentation) waits for an echo on the request. It does not define the time between two successful requests. Therefore this option can't be used to fine tune the delay on pinging the IP address 127.0.0.1 as this request is successful in less than 1 millisecond and value of option -w does not matter.
So for a delay in milliseconds instead of seconds it is necessary to ping an IP address which is definitely or at least most likely not reachable and which is not routed via networks because of being a private network address according to RFC 6761.
An example is:
%SystemRoot%\System32\ping.exe 168.192.255.253 -n 1 -w 1500
The IPv4 address range from 168.192.0.0 to 192.168.255.255 is for private networks. The highest address 192.168.255.255 in this network is the broadcast address and is not used for devices. It is common to configure a router with local area network broadcast address minus 1 which means 192.168.255.254 could be assigned to a router in case of current computer is part of this private network. And other devices in a LAN get assigned usually the IPv4 addresses from lowest address plus 1 upwards. Therefore for IPv4 network 168.192.0.0/16 the IP address 168.192.255.253 is most likely not assigned to any device which would respond on the echo request of PING.
Well, the milliseconds delay is not very accurate. But is it really important on execution of a batch file to wait exactly 1500 ms?
Note 2: This approach does not work if the computer on which the batch file is running is currently not connected to any network. Without any network connection each echo request is always immediately terminated and PING outputs for each echo request the error message:
PING: transmit failed. General failure.
The general failure is no network (connection) present at all and therefore only echo requests to local loopback adapter work.

Answer 2

Unfourtanelty, #thx1138v2's solution only delays 0.04 seconds on my machine. Therefore, I've modified his solution to make it more accurate.
ping 1.1.1.1 -n 1 -w 1500 >nul
1500 stands for 1500 milliseconds, which is 1.5 seconds.
ping is inaccurate when pinging a small amount of time, see this table:
Milliseconds In Code | Actual Waited Time
1500 | 1.24 seconds - 1240 milliseconds
1600 | 1.34 seconds - 1360 milliseconds
1700 | 1.52 seconds - 1520 milliseconds
As you can see, 1700 ms's wait time is much precise than 1500 ms, so you may need to consider some extra milliseconds.
Note: ping only supports delay more than 99 milliseconds

Answer 3

-n is the (n)umber of times to ping, not the amount of time to wait. You can't ping 1.5 times.
-w is the time to (w)ait on each ping in milliseconds. To pause 1.5 seconds would be
ping -n 3 -w 500
If there is a web site set up on the machine running the batch file the ping will find it as localhost and the timeout will not apply. The timeout only applies to failed requests. It is better to ping 0.0.0.1 for a delay.
ping -n 3 -w 500 0.0.0.1