Oh! But how would I know without 'running' it, if its ok?

Have you come across your teammates, checking in scripts without running it, with syntax errors, malformed XML documents, broken Makefiles .... well, there is some hope, you could help (by sharing this link! :-) )

Mostly, if its code in a compiled language (like C), developers at least compile the code (might not test!) before checking into version control. But, in case of XML documents, scripts etc, the code gets checked in, and it will not error out until some test case is completely run, or in the nightly regressions!

Its not really difficult to do some basic validation of scripts, Makefiles, or even XML documents before a check-in. Most languages/tools have an option to do basic checks - syntax checks, dry run (without actually executing the commands), bytecode generation etc. Here are some, which I often use:

Make

make -n

Does a dry-run, shows which targets would get built on an actual run.

Perl

perl -c

Does a compilation and says if syntax is OK or not (there are caveats with BEGIN blocks, but at least there is something!)

Python

pycompile

This is good, there is a separate utility to do the compilation! (just run pycompile on your scripts once before you proceed)

bash

bash -n

Again, syntax checks without actually executing anything.

XML

xmllint

The name says it all! Even though there are plenty of options, you could just run once [without even options] on your XML docs to see if its well-formed.

Lua

luac

Lua bytecode compiler, like pycompile. Generates luac.out which you can delete :-)