What do the & and | operators do in a batch file?

Question

I'm debugging a batch file left behind by an old employee and I've come across the line:

@nmake -f makefile /E 2>&1 | tee %LOGFILEPATH%  

What does this do?
I know what @nmake -f makefile /E does and I know what tee %LOGFILEPATH% does, but I can't find anything on what the 2>&1 | means.
Thanks

Answer 1

2>&1 redirects standard error to standard out.

| pipes the output from nmake into tee.

Answer 2

2>&1 redirects the standard error stream to standard output.

The pipe | redirects standard output of the first command to the standard input to the second command.

So your command, bunches all output from nmake and redirects it all to tee

Answer 3

See http://stackoverflow.com/questions/414715/a-bat-or-wsh-script-that-can-search-for-files/415222#415222