Hello,
today I isseud a `sudo npm update -g` command but it failed
```
info it worked if it ends with ok
verbose cli [ 'node', '/usr/local/bin/npm', 'update', '-g' ]
info using npm@1.0.3
info using …
I'm getting very frequent, but intermittent, errors with installing packages on cygwin (Windows 7 x64). These errors always seem related at something like:
```
ERR! Error: Failed tar "-mvxpf" "-" "…