Visit Michel Pollet's home page where you can download his "Linux Disks" application.
It has an excellent user interface and allows you to open your Linux partitions from the MacOS.

http://w3.teaser.fr/~mpollet/LinuxDisks/ 

Matt Warner, mwarner1@ix.netcom.com

There are also reports of problems with 1.0d7. For now (7/98), I guess you should avoid using LinuxDisks, and instead use the MkLinux commands above.

hollis@andrew.cmu.edu

However, if you just need read-only access to files on ext2fs disks, you should try out MountX, a GPL'd ext2fs mounter by Ben H. http://calvaweb.fr/bh40. It works reliably now, on both SCSI and IDE disks. One note is that it is a security risk -- all files are mounted as if they had NO permissions at all!!

Assuming you compiled HFS support into your kernel, you can have read and write to HFS disks just like any other type of disk. Just mount your drive using a command like this:
mount -t hfs /dev/hda8 /mnt
You should be able to safely read and write files to this disk. If you are using really old kernel (such as 2.1.124) you should upgrade your kernel, otherwise reading / writing files may cause Linux to crash or mess up your HFS partition (usually B-tree corruption). You can usually fix such corruption by running Norton Disk Doctor in the Mac OS, but not always.

The best route is to make sure you have a modern kernel.
arthur99@global2000.net