When I build a package, I want a log so I can check for errors once the process has finished. I use this:
./<buildscript> 2>&1 | tee <buildscript.log>
Where <buildscript> is the name of the script I'm using for the package build. 2>&1 combines standard error output with normal console output, which is piped to the tee utility (which should be found in pretty much every Linux installation). That way, I see the output on screen, but also have a log file to examine later if I need to.