[ShyGuy91284]

I want to reinstall OS X on my laptop. Is backing up my settings and stuff for applications as easy as it would be in Unix/Linux (tarring up my home directory, and untarring it in the reinstal), or is there another way I should do it? I do not have a .mac account (as I have read can sometimes be used for stuff like this).

[SpaceMonkey]

Just select "archive and install" when you reinstall OS X. This will archive your previous system in its own folder and create a fresh install of OS X, leaving your user account untouched. You can then delete the previous system at your leisure.

[rehoot]

tarring will work, but you may want to tar each of the directories in the root in a separate tar file. There are a couple files in the root directory that are system files that you probably don't want to touch.

You may also want to download a program called xtar by a company called Helios. This will help you to preserve some of the file attributes that are lost by the regular tar (such as special colors applied to a filename). For some reason, I also needed Disk Warrior to restore the colors that I applied to filenames--but that isn't too important.

[rehoot]

I just remembered that the best way to restore an entire drive is to boot from a CD so that none of the files on the hard drive are locked. I used a program called BootCD to create a Mac OS X bootable CD, then I booted from that to perform the archive and restore.

Before you do this, be sure that you copy essential programs to your external hard drive and ensure that you can access them when you boot from the CD. Here are some important programs:

tar
xtar
gzip
gunzip (same as gzip)
ditto
emacs (or vi or vim or pico or your favorite line editor)

If you archive each directory in the root and then boot from a CD, you can delete each of those directories (and empty the trash can) and when you recopy all the files to the hard drive your drive will also be defragmented. Remember that you can't delete the files in the root and you CANNOT delete the following directories from your root without causing problems:

automount
Volumes
dev
TheVolumeSettingsFolder
.hidden
mach_kernel

I created the list above via trial and error after I reformtted my hard drive and restored it to its original state using my archive. I have this in a script so that I can save my entire hard drive, wipe it (most of it) and then restore it to defrag my drive --- and yes, you do need to ocassionally defrag Mac OS X if you have big files or do lots of appending to existing files.

[rehoot]

I just remembered that the best way to restore a Mac OS X hard drive from tar files is to boot from a CD. I found a program called BootCD that allowed me to create the boot CD. You can then boot from that CD and restore files to your hard drive without having to worry about system files being locked.

Before you do this, you need to be sure that you have all the important programs either on the CD or on your external drive, and ensure that you can get to them. Here are some important program that you need on the external drive:

tar
xtar
gzip
gunzip (same as gzip)
ditto
emacs (or vi or vim or pico or another line editor)

Ideally you would boot from the CD and make the backup, and boot from the CD to restore it, however, YOU CANNOT DELTE THE FOLLOWING DIRECTORIES WITHOUT CAUSING PROBLEMS (I learned this by trial and error):

/Volumes
/dev
/TheVolumeSettingsFolder
/automount
/mach_kernel
/.hidden

If you have a good archive and you run into trouble, just reformat the drive and then restore your files. I did this a couple months ago to defrag my Mac OS X hard drive -- yes you need to do this if you use big files that are updated frequently. My script tars each directory in the root then, while booted from a CD, deletes all those directories (except the ones listed above) and then restores the tar files in an order that approximates the order in which they are used at boot:
/cores, /bin, /sbin, /private, /usr,/System, /Library and so on.

After I did this, my hard drive was defragged and had lots of contiguous free space.