batch file to loop only 3 times...

[kalasha]

i have a batch file that works for backing up but i just need to tweak one section of it.

the batch file first checks to see if the computer can access the internet.  if not, it waits 5 minutes and tries again.  the problem is, it can do this continously.  i only want to check availability several times (3 to 5 times max,) not continously.

>>
:AMIALIVE
ping www.google.ca
if "%errorlevel%" NEQ "0" (ECHO %date%, %Time% The Internet is not available.  The backup will be delayed 5 minutes. >>C:\History\Report.txt
TIMEOUT 300
GOTO AMIALIVE
) ELSE (ECHO %date%, %time% The Server is available, attempting to connect to the vpn. >>C:\History\Report.txt
)
>>

can the above be changed so that the batch file checks for connectivity only 3 times.  there are only three possible scenarios for this
ex. first attempt gets a reply from the ping, so it continues with establishing the vpn and continues with xcopy
or
first attempt fails to get ping reply (do not care why) so there is a 5 minute delay before retrying.  second attempt works so (no need to retest connection a third time) it continues with establishing the vpn....
or first, second, and third attempt fails, so it gives up and goes to EOF.

thank you,

jat

[Sidewinder]

More and more posters are using this technique for errorlevels:

Code: [Select]

if "%errorlevel%" NEQ "0"

Is this documented anywhere? If so where.

Anyway, this may help:

Code: [Select]

@echo off
for /l %%v in (1,1,3) do (
ping www.google.ca
if not errorlevel 1 goto iamalive
ECHO %date%, %Time% The Internet is not available.  The backup will be delayed 5 minutes. >>C:\History\Report.txt
if %%v==3 goto :eof
TIMEOUT 300
)
:IAMALIVE
ECHO %date%, %time% The Server is available, attempting to connect to the vpn. >>C:\History\Report.txt

Good luck. 

I'm guessing that TIMEOUT is some sort of timer utility.

[Dias de verano]

You beat me to it, Sidewinder! I couldn't resist polishing my attempt

1. Informative version

Code: [Select]

@echo off

REM test success mode
set server=www.google.ca

REM test fail mode
REM set server=www.xqyrrrabc.com

set limit=5

for /L %%T in (1,1,%limit%) do (

Echo Attempting to ping %server%

REM using && (success) operator
REM opposite operator is || (failure)
ping %server% && goto ALIVE

        echo Ping attempt %%T of %limit% failed.
ECHO %date%, %Time% The Internet is not available.  The backup will be delayed 5 minutes.>> C:\History\Report.txt
echo Waiting 300 seconds.
TIMEOUT 300
echo.
)

REM If you got here, the internet is NOT available, checked %limit% times.
echo Internet not available.
goto DEAD

:ALIVE

REM If you got here, the internet IS available & you can attempt the vpn

     ECHO %date%, %time% The Server is available, attempting to connect to the vpn. >> C:\History\Report.txt

Echo attempting to connect to VPN and perform Xcopy.
REM Code to be executed if internet is available
goto NEXT

:DEAD
     REM code to be executed if internet is NOT available

:NEXT



2. Shorter functional version

Code: [Select]

@echo off
set server=www.google.ca
set limit=5
for /L %%T in (1,1,%limit%) do (
ping %server%>nul && goto ALIVE
ECHO %date%, %Time% The Internet is not available.  The backup will be delayed 5 minutes. >> C:\History\Report.txt
TIMEOUT 300
)
goto DEAD
:ALIVE
     REM Code to be executed if internet is available
     ECHO %date%, %time% The Server is available, attempting to connect to the vpn. >> C:\History\Report.txt
     goto NEXT
:DEAD
     REM Code to be executed if internet is NOT available

:NEXT


More and more posters are using this technique for errorlevels:

Code:

if "%errorlevel%" NEQ "0"


Is this documented anywhere? If so where.

I'm not sure where this is documented by Microsoft; there are any number of places that discuss NT system variables.

In "regular MS-DOS" 16-bit command language, as found in MS-DOS/Win95/98/ME, you were able to test only thus: if errorlevel N (do something). No percent signs, so that errorlevel was not an ordinary variable, and N could be any nonzero integer from 1 to 255 (failure) or 0 (success). Note that "if errorlevel 1 " meant "if errorlevel is 1 or more". This method of testing errorlevel is continued in 32 bit command language.

If you wanted to find out what a nonzero value was, you had to test all values from 255 downwards thus.

if errorlevel 255 set eval=255
if errorlevel 254 set eval=254
[...]
if errorlevel 1 set eval=1

Or if you knew the topmost possible errorlevel for the program which just exited, you could start there. Tedious, I think you will agree.

However, in 32 bit command language, i.e. since Windows NT4, the "width" of errorlevel increased from 1 byte (0 to 255) to 2 bytes (0 to 65535) which makes the above method even more tedious (!) to code, and I suspect that is why we saw the introduction of the system variable %errorlevel%, the error code of the most recently used command, which allows the type of test you have noticed, where you can test for any value in one line of code.

I'm guessing that TIMEOUT is some sort of timer utility.

Seems to mimic the SLEEP command contained in the  Windows 2003 Resource Kit.

[Sidewinder]

Thanks Dias. I pretty much knew what you wrote about errorlevels from my experience with a Java application which kept throwing an errorlevel 9009. Took a while to wrap my head around that one.

At least the original method still works, unlike Microsoft playing Where's Waldo with the choice command.

 

[Dias de verano]

I know people say "you can't polish a turd", but that doesn't seem to stop Microsoft trying to make their scripting language more shiny...

[kalasha]

TIMEOUT ### is a Vista dos command (my O/S).  It is the same as the Sleep utility that i downloaded from computerhope.com for the xp towers.

SLEEP does not show how much time is left, it just shows ### seconds
TIMEOUT ### shows a countdown from ### seconds to 0 seconds.  I use TIMEOUT on Vista to test the backup that i am writing... rename SLEEP to TIMEOUT and see if utility works...

the code: if "%errorlevel%" NEQ "0" was from another site and the original post user wanted to do the same thing that i wanted to do - check server availability.  It was not explained on that site how the small line works, except that if there were no errors it would continue as instructed, but you need to know the code for no errors - 0 in most cases for me because i do not have any other utilities or software.

thanks

jat

[kalasha]

I used the code as follows:

ECHO %date%, %time% Initiating back up...>>C:\History\Report.txt
:AMIALIVE
   set server=www.google.ca
   set limit=5
   for /L %%T in (1,1,%limit%) do (
      ping %server%>nul && goto VPN
      ECHO %date%, %time% The Internet is not available.  The backup will be delayed 5 minutes. >> C:\History\Report.txt
      TIMEOUT 300
   )
   goto EOF

the Report.txt file does not update the time... it looks like this:

19/07/2008, 11:08:33.87 Initiating back up...
19/07/2008, 11:08:33.88 The Internet is not available.  The backup will be delayed 5 minutes.
19/07/2008, 11:08:33.88 The Internet is not available.  The backup will be delayed 5 minutes.
19/07/2008, 11:08:56.23 The Server is available, attempting to connect to the vpn.

should the time not update, or how do i get it to update automatically?

jat

[Dias de verano]

The TIMEOUT syntax is

timeout /t [seconds]

so I suspect you need to edit that.