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

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 开发者_高级运维what tee %LOGFILEPATH% does, but I can't find anything on what the 2>&1 | means.

Thanks

---

2>&1 redirects standard error to standard out.

| pipes the output from nmake into tee.

---

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