Homebrew Warnings? - macos

Question

Just installed Homebrew but for some reason when I did "brew doctor" I kept getting these warnings and when i run the commands chown that it gives me, nothing happens...
> brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry and just ignore them. Thanks!
Warning: /usr/local/include isn't writable.
This can happen if you "sudo make install" software that isn't managed by
by Homebrew. If a formula tries to write a file to this directory, the
install will fail during the link step.
You should probably `chown` /usr/local/include
Warning: /usr/local/lib isn't writable.
This can happen if you "sudo make install" software that isn't managed by
by Homebrew. If a formula tries to write a file to this directory, the
install will fail during the link step.
You should probably `chown` /usr/local/lib
Warning: /usr/local/lib/pkgconfig isn't writable.
This can happen if you "sudo make install" software that isn't managed by
by Homebrew. If a formula tries to write a file to this directory, the
install will fail during the link step.
You should probably `chown` /usr/local/lib/pkgconfig
Warning: /usr/local/sbin isn't writable.
This can happen if you "sudo make install" software that isn't managed by
by Homebrew. If a formula tries to write a file to this directory, the
install will fail during the link step.
You should probably `chown` /usr/local/sbin
Warning: Some directories in /usr/local/share/man aren't writable.
This can happen if you "sudo make install" software that isn't managed
by Homebrew. If a brew tries to add locale information to one of these
directories, then the install will fail during the link step.
You should probably `chown` them:
/usr/local/share/man/man8
Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Unexpected dylibs:
/usr/local/lib/libntfs-3g.80.dylib
/usr/local/lib/libntfs.9.0.0.dylib
/usr/local/lib/libublio.1.dylib
Warning: Unbrewed header files were found in /usr/local/include.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Unexpected header files:
/usr/local/include/ntfs/attrib.h
/usr/local/include/ntfs/attrlist.h
/usr/local/include/ntfs/bitmap.h
/usr/local/include/ntfs/bootsect.h
/usr/local/include/ntfs/collate.h
/usr/local/include/ntfs/compat.h
/usr/local/include/ntfs/compress.h
/usr/local/include/ntfs/debug.h
/usr/local/include/ntfs/device.h
/usr/local/include/ntfs/device_io.h
/usr/local/include/ntfs/dir.h
/usr/local/include/ntfs/endians.h
/usr/local/include/ntfs/gnome-vfs-method.h
/usr/local/include/ntfs/gnome-vfs-module.h
/usr/local/include/ntfs/index.h
/usr/local/include/ntfs/inode.h
/usr/local/include/ntfs/layout.h
/usr/local/include/ntfs/lcnalloc.h
/usr/local/include/ntfs/list.h
/usr/local/include/ntfs/logfile.h
/usr/local/include/ntfs/logging.h
/usr/local/include/ntfs/mft.h
/usr/local/include/ntfs/mst.h
/usr/local/include/ntfs/ntfstime.h
/usr/local/include/ntfs/rich.h
/usr/local/include/ntfs/runlist.h
/usr/local/include/ntfs/security.h
/usr/local/include/ntfs/support.h
/usr/local/include/ntfs/tree.h
/usr/local/include/ntfs/types.h
/usr/local/include/ntfs/unistr.h
/usr/local/include/ntfs/version.h
/usr/local/include/ntfs/volume.h
/usr/local/include/ntfs-3g/acls.h
/usr/local/include/ntfs-3g/attrib.h
/usr/local/include/ntfs-3g/attrlist.h
/usr/local/include/ntfs-3g/bitmap.h
/usr/local/include/ntfs-3g/bootsect.h
/usr/local/include/ntfs-3g/cache.h
/usr/local/include/ntfs-3g/collate.h
/usr/local/include/ntfs-3g/compat.h
/usr/local/include/ntfs-3g/compress.h
/usr/local/include/ntfs-3g/debug.h
/usr/local/include/ntfs-3g/device.h
/usr/local/include/ntfs-3g/device_io.h
/usr/local/include/ntfs-3g/dir.h
/usr/local/include/ntfs-3g/efs.h
/usr/local/include/ntfs-3g/endians.h
/usr/local/include/ntfs-3g/index.h
/usr/local/include/ntfs-3g/inode.h
/usr/local/include/ntfs-3g/layout.h
/usr/local/include/ntfs-3g/lcnalloc.h
/usr/local/include/ntfs-3g/logfile.h
/usr/local/include/ntfs-3g/logging.h
/usr/local/include/ntfs-3g/mft.h
/usr/local/include/ntfs-3g/misc.h
/usr/local/include/ntfs-3g/mst.h
/usr/local/include/ntfs-3g/ntfstime.h
/usr/local/include/ntfs-3g/object_id.h
/usr/local/include/ntfs-3g/param.h
/usr/local/include/ntfs-3g/reparse.h
/usr/local/include/ntfs-3g/runlist.h
/usr/local/include/ntfs-3g/security.h
/usr/local/include/ntfs-3g/support.h
/usr/local/include/ntfs-3g/types.h
/usr/local/include/ntfs-3g/unistr.h
/usr/local/include/ntfs-3g/volume.h
/usr/local/include/ublio.h
Warning: Unbrewed .la files were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Unexpected .la files:
/usr/local/lib/libntfs-3g.la
/usr/local/lib/libntfs.la
/usr/local/lib/libublio.la
Warning: Unbrewed .pc files were found in /usr/local/lib/pkgconfig.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Unexpected .pc files:
/usr/local/lib/pkgconfig/libntfs-3g.pc
/usr/local/lib/pkgconfig/libublio.pc
Warning: Unbrewed static libraries were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.
Unexpected static libraries:
/usr/local/lib/libntfs-3g.a
/usr/local/lib/libntfs.a
/usr/local/lib/libublio.a
Warning: Some directories in your path end in a slash.
Directories in your path should not end in a slash. This can break other
doctor checks. The following directories should be edited:
/sw/bin/ /usr/local/ /usr/local/bin/

Answer 1

Did you issue the "brew doctor" as root/Administrator (whatever they call it in Mac)? If not, do
su Administrator
and try again.
It seems that the user that issued the command had no permissions to write in /usr/local/ subdirectories. The Administrator should be able to write in this directory structure. If that is not the case, something is terribly wrong with your system (if you are not by any chance on a read only disk).
Your user account should - for the sake of your system's computer security - never be able to write in /usr/ or any of its subdirectories.
There may, however, be reasons to not have homebrew handled directly by the admin user. If you want to set up a non-admin user specifically for dealing with homebrew, you can for instance try this solution. In short, they suggest to create a new user (homebrew), chown the relevant /usr/ subdirectories so that they are then owned by the homebrew user (which I think is not a good idea since they should be owned by the admin user and since it would be sufficient to adjust the group permissions and add homebrew into the admin group), and remove the homebrew user from the login page. Then homebrew can be set up and later be used after issuing
su homebrew
Regarding chown (I do not think this is required for the problem at hand, but I'd like to explain it): chown should in case of failure always give an error message. The syntax is
chown <new owner> <file or directory>
with optionally the group and a number of possible options added as explained in the man page. In case that really nothing happens and no error message, the -v option can be used to cause chown to give verbose output - in that case, it should be detailed to the point of saying
ownership of <file/directory> retained as <owner>
or
changed ownership of <file/directory> from <old owner> to <new owner>