An Introduction to Unix Permissions -- Part Two
This is the second of a two-part series article that continues the tutorial on Unix permissions and shows us how to modify them using 'chmod'.
Archiving with Pax
In today's article, I'd like to finish up the archiving series with the pax utility. It's unfortunate that this utility never seems to get the coverage that tar and cpio do. I've found that it combines the best qualities of both utilities into one easy-to-use and fairly intuitive utility.
Backing up Files with Tar
In my last article, I introduced the concept of archivers; today I would like to demonstrate the usage of the tar archiver. Since we'll be backing up and restoring files, I recommend that you create a test user account to practice with until you are comfortable using the tar utility
Dealing with Full Disks
So, your daily message shows that your partitions are getting full. (You do read your daily status mail, right? Of course you do.) While various desktop environments have nifty point-and-click interfaces that show you exactly where your disk space went, they don't help much when your GUI-less server starts having trouble. We're going to look at some basic disk measuring tools, with the goal of finding that missing few gigabytes of space.
Dividing Your Data
In the next few articles, I'll look at how FreeBSD stores data on your hard disk. To store data on a hard drive, the drive must first be divided into logical storage units, and each unit must be assigned an address. The file system will save data to these storage units and keep track of which storage units contain which files.
Finding Things in Unix
One of the most useful utilities to be found on any Unix system
is the find command. In the next two articles, I'd like to work
you through the syntax of this command and provide you with
some practical examples of its usage.
Finding Things in Unix: Part Two
In the last article, I introduced the Unix find command. This
week, I'd like to continue by demonstrating some more of the
switches that are available with this handy command.
JFS overview
JFS provides fast file system restart in the event of a system crash. Using database journaling techniques, JFS can restore a file system to a consistent state in a matter of seconds or minutes, versus hours or days with non-journaled file systems. This white paper gives an overview of the architecture, and describes design features, potential limits, and administrative utilities of the JFS technology available on developerWorks.
Mounting Other Filesystems
Filesystem incompatibility can be a real pain, especially amongst Windows operating systems. Fortunately BSD has a few tools to handle the situation.
Stable SMB
I discussed FreeBSD's SMB filesystem support well over a year
ago. At the time, it was highly experimental and suffered
occasional seizures. It has since improved to the point where
it is reliable enough for use in production settings. If you
want to access a Windows share from your FreeBSD workstation,
this is how you do it.
Understanding Archivers
In the next few articles, I'd like to take a look at backups and archiving utilities. If you're like I was when I started using Unix, I was intimidated by the words tar, cpio and dump, and a quick peek at their respective man pages did not alleviate my fears.
Understanding CPIO
In the previous article, I demonstrated the usage of the tar archiver utility. This week I'll continue by introducing the cpio archiver utility. While both tar and cpio will achieve the same results, the cpio utility approaches things a little bit differently. The tar utility assumes that you want to recursively archive everything under the specified directory or directories, meaning that you have to explicitly tell tar if you want to exclude certain portions of that directory structure.
Understanding Filesystem Inodes
We've spent the last few articles looking at partition tables and file systems. We've discovered that your PC finds your FreeBSD slice by reading the BIOS partition table. That FreeBSD slice has a Unix partition table that contains the "disk packing label," which describes the layout of the filesystems on that slice. This week, we can finally take a look at inodes: what they are and what information about them is available to you on your FreeBSD system.
Understanding FreeBSD Disklabels
"Disklabel" is a term many people brush off on those occasions
when they hear it. Once you have a running system, you don't
need to worry about disklabels. Most BSD operating systems
gloss over the details of disklabels during the install
process, making a new user's life slightly easier. (OpenBSD
actually brings a user into fairly intimate contact with the
disk, but it's the exception.) One day when things go wrong,
however, you'll wish you understood disklabels.
Understanding NFS
We've discussed sharing filesystems via SMB a few times. SMB
lets you access files shared by a Windows system after jumping
through only half a dozen loops. Sharing files with another
Unix system is much, much simpler. FreeBSD supports the Unix
standard Network File System out of the box. NFS intimidates
many junior system administrators, but it's really quite simple
once you know what's going on
Understanding Unix Filesystems
In last week's article, we viewed a PC's BIOS partition table and its Unix partition table using the fdisk and disklabel utilities. Let's continue this week by looking at the newfs utility and inode tables. The newfs utility actually formats your slice with the filesystems you previously specified with the disklabel utility. Let's start by taking a closer look at formatting and filesystems in general so we can gain a better appreciation of newfs.
Who Has Which Files
One morning when there just didn't seem to be enough caffeine in the world, I decided to avoid dealing with people and just clean up all the little jobs on my to-do list. One task was to put a CD-ROM into a particular machine and copy files from it to the hard drive. Seems simple enough, doesn't it?
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