It might not be a surprise to you, but Windows commands inside cmd.exe does not change errorlevel as you might expect.
For example running a echo something > c:\somefile.txt, which will succeed actually creating the file, but not change errorlevel to 0. You can test it like this:
md 2>nul
echo %errorlevel%
1
echo this.works > c:\test.txt
echo %errorlevel%
1
type c:\test.txt
this.works
This echo can not really be solved by using cmd /c echo because that will just always succeed, for example:
md 2>nul
echo %errorlevel%
1
cmd /c echo this.works > c:\test.txt
echo %errorlevel%
0
type c:\test.txt
this.works
cmd /c echo this.fails > drivedoesnotexist:\test.txt
The filename, directory name, or volume label syntax is incorrect.
echo %errorlevel%
0
And now, testing if copy command file1 + file2 into file3 gives errorlevel 1 if one of the source files does not exists. Errorlevel 1 is what you might expect, but it is not the case here:
echo 1 > 1.txt
rm 2.txt
echo 3 > 3.txt
ls -la 2.txt
ls: File or directory "2.txt" is not found
copy /b 1.txt + 2.txt + 3.txt 123.txt
1.txt
3.txt
1 file(s) copied.
echo %errorlevel%0
This is not as I expected, I will want to find a way to get around this.
There are probably same problem with other cmd commands, I didnt try others.
Maybe I am doing something the wrong way, in my environment and installation ... need to investigate :-)
I have not been able to find anything in the cmd command line reference, and it does not seem to solvable if everything is put into a batch script, instead of running commands one by one. I did hope that, because of text on information about setlocal ENABLEEXTENSIONS which can be set in a script, but has no effect on the command prompt:
cmd does not set the ERRORLEVEL variable when command extensions are
disabled
But unfortunately it did not work, here is the run.cmd script i ran:
setlocal ENABLEEXTENSIONS
echo 1 > c:\1.txt
rm c:\2.txt
echo 3 > c:\3.txt
copy /b c:\1.txt + c:\2.txt + c:\3.txt c:\123.txt
echo %errorlevel%
endlocal
The above echo'd 0 and the errorlevel after the script is 0. So not a solution!
I still keep investigating :-)
Oh yeah - in case you ever wondered, you should never manually set the errorlevel to 0 or 1 or whatever you need. Instead you should always use a command for that. I am using "ver" to get errorlevel 0 and "md;2>nul" to get errorlevel set at 1, which I found on one of my favorite batch example webpages.
