We then have a QA and Showcase build that we can run to deploy all the artifacts necessary to launch the application on that machine.

Originally I had just written the batch script to take in the tag of the build which the user could find by looking through repo-browser for the last tag created. This quickly became very tedious so I started looking for a way to get the latest tagged revision from the command line.

We thought it would be possible to get this information using svn info but it turned out that the information returned by svn info about revisions doesn’t necessarily refer to the latest created tag. We ended up using svn log and then parsing through that data. It’s a bit messy but it does the job (I name each tagged version of the code as ‘build-{TeamCity-Build-Number}):

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FOR /F "Tokens=2" %%i in ('svn log /tags/path --limit=1 -v ^| find "build"') do set TMP=%%i
FOR /F "Tokens=2 delims=/" %%i in ('echo %TMP%') do SET TAG=%%i

The for loop uses a space as its default delimiter so that’s what the ‘delims=/’ is doing on the second line, the ‘Tokens=2′ allows us to get the second token after the string is split and the ‘^’ in the first command is being used to escape the pipe.

I always found it really frustrating when using the windows command prompt that I couldn’t get Unix style tab auto completion. To navigate my way to a directory I would do the following:

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C:\>cd Downloads

C:\Downloads>cd nant-0.85

C:\Downloads\nant-0.85>cd bin

C:\Downloads\nant-0.85\bin>

It is very tedious as you might imagine. I would try placing a forward slash after each directory in the hope that it would allow me to scroll through the next directory down but to no avail.

Little did I know that in fact I needed to be using the backslash. The above can now be done in one line using Unix style tabbing auto completion:

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C:\>cd Downloads\nant-0.85\bin

C:\Downloads\nant-0.85\bin>

I thought it would be relatively simple, but after various searches and having read articles that suggested that there wasn’t an ELSE construct in batch land I finally found a forum post which explained how to do it.

The script I’m working on takes in a working directory as one of the arguments and what I wanted to do was either set a variable to be the value passed in, or if the value passed in was ‘.’ then to set it to the current working directory.

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IF "%1"=="."  (
  set WORKING_DIRECTORY=%cd%
) ELSE (
  set WORKING_DIRECTORY=%1
)

I played around with this a little bit and it does seem that the brackets need to be in that exact format otherwise it doesn’t work at all. Even putting brackets around the IF part of the statement will stop the script from working as expected.

IF statements on their own are much easier to deal with. To check for an empty argument for example either of the following will work:

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IF "%1"=="" GOTO usage

IF [%1]==[] GOTO usage

It does all seem a bit fiddly and Powershell is probably the way forwards, but for now batch scripts it is!

In Unix it’s easy, just call ‘pwd’ and you have it. I wasn’t expecting something that simple in Windows but it is! A call to ‘cd’ is all that’s needed. If you need to set it in a batch script the following line does the trick:

set WORKING_DIRECTORY=%cd%

I was surprised that something so simple (I do now feel like an idiot) wasn’t easier to find on Google. I ended up going via Experts Exchange (how they end up with such high search results when you have to pay to see the information is beyond me) and several other verbose ways of solving the problem before finally coming across this article which explained it.