A filesystem is a way to organize and store computer files with their data.

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Where do open file handles go when they die?

What happens to the files that are deleted while they have a file handle open to them? I have been wondering this ever since I figured out I could delete a video file while it was playing in MPlayer ...
6
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2answers
5k views

How does linux work with symbolic links?

I mean what's going on when some process wants to read a symlink? What's going on when something changes a symlink during a read or even write process? For example: I have 2 huge, similar 100G files ...
4
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2answers
1k views

Salvaging a “broken” hard drive

My girlfriend's macbook's hard drive failed, so I gave her a new one and reinstalled OSX on it. Works fine. However, I wanted to see if I could use her old hard drive for backups/fun. I was able to ...
29
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5answers
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How can I increase the number of inodes in an ext4 filesystem?

I had a problem (new to me) last week. I have a ext4 (Fedora 15) filesystem. The application that runs on the server suddenly stopped. I couldn't find the problem at first look. df showed 50% ...
8
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4answers
4k views

Safely use SD cards when power can go out at any time

We're working on a small embedded Linux system (2.6.35-ish) with a smallish internal NAND device for the OS and applications (250-500Meg) and an SD card with 8Gb SDHC SD cards for data. The unit's ...
15
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3answers
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(How) can I create a tmpfs as a regular (non-root) user?

The distribution is an Ubuntu server running the 2.6.35-30 Linux kernel. I would like to have a directory that sits completely in memory. Is this possible without root privileges?
7
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2answers
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ISO file readonly?

I have an ISO file and I mount it under /mnt/isofile. Then I copied this file to another folder. But the contents are read-only and belonged to root. I tried to use chmod and chown. But it prompts ...
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0answers
97 views

At the root level (/) directory, why is that .. refers to itself? [duplicate]

Possible Duplicate: Why does '/' have an '..' entry? I understand that in the filesystem hierarchy starting with / as top-level directory, under which all the other sub ...
10
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3answers
4k views

Make changes to /sys persistent between boots

I want to make "echo 1 > /sys/kernel/mm/ksm/run" persistent between boots. I know that I can edit /etc/sysctl.conf to make /proc filesystem changes persist, but this doesn't seem to work for /sys. ...
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1answer
285 views

How can I tell when a file was modified?

I am running some simulation on a high performance computing cluster (HPC). When I check when the file was changed with ls -t I get the wrong result. I know this becouse I have run a small job that ...
2
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0answers
130 views

Can't mount remote file system with sshfs [duplicate]

Possible Duplicate: How to apply changes of newly added user groups without needing to reboot? I have posted this question in linux mint users forum about some hours ago. I'm trying to ...
36
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5answers
65k views

Script to monitor folder for new files?

How do I detect new files in a folder with a bash script? I would like to process the files as soon as they are created in the folder. Is this possible to do so or do I have to schedule a script with ...
1
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2answers
2k views

Choosing a filesystem for a shared disk (not a cluster filesystem like GFS)

I have a bunch of servers connected to a SAN. One server hosts the production database server, performing full database backups to a filesystem on a LUN that is exported to all servers. Only the ...
5
votes
3answers
2k views

What filesystems can be shrunk online in 2011?

I'm asking because, for example, https://en.wikipedia.org/wiki/Comparison_of_file_systems#Features states that EXT3 can be shrunk online. But when I click on the reference: "Offline ...
2
votes
1answer
8k views

Mounting ufs partition with read/write permissions on ubuntu 10.04

According to this writeup ufs kernel module is compiled with only read permissions. I could mount a ufs partition with this command: sudo mount -t ufs -r -o ufstype=ufs2 /dev/mapper/loop0p1 ...
16
votes
2answers
430 views

How does “rm” on a NTFS filesystem differs from Windows' own implementation?

I have an external USB disk with an NTFS filesystem on it. If I remove a file from Windows and I run one of the several "undelete" utilities (say, TestDisk) I can easily recover the file (because ...
5
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3answers
3k views

What do first column in /proc/mounts really mean in Linux?

Run cat /proc/mounts and I get this (simplified): rootfs / rootfs rw 0 0 proc /proc proc rw,relatime 0 0 /dev/sda1 / ext3 rw,relatime,errors=continue,barrier=1,data=ordered 0 0 io /etc/blkio cgroup ...
3
votes
2answers
1k views

How does Linux keep track of filesystems?

As I know, Linux has an abstract layer of all filesystems and this layer is VFS. If I create a new filesystem, I should follow rules made by VFS (see "Anatomy of the Linux virtual file system switch" ...
44
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2answers
170k views

How to get the complete and exact list of mounted filesystems in Linux?

I usually use mount to check which filesystems are mounted. I also know there is some connection between mount and /etc/mtab but I'm not sure about the details. After reading How to check if /proc/ is ...
1
vote
1answer
339 views

Do memory-backed filesystems (like sysfs and procfs) have superblock and inode table?

From "Design and Implementation of the Second Extended Filesystem" I know that ext2 has superblock and inode table stored in disk and superblock will be accessed when mounting the filesystem. Do ...
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votes
1answer
2k views

List mount points owner and group [closed]

I'm running HPUX 11.x and I was wondering if there's a command that would list all the mount point owner and group. I want a listing like df or bdf but with ownership information.
2
votes
0answers
99 views

“cd //” and “cd /” what is the difference? [duplicate]

Possible Duplicate: unix, difference between path starting with '/' and '//' If I make a cd // followed by a pwd I see: # cd // # pwd // why is that? what's the differece ...
1
vote
1answer
8k views

How to decrease the size of a logical volume/fs aix?

oslevel -s 6100-03-03-0943 IF I have a Logical Volume that I need to shrink, then how can I do it? [there could be several FileSystems on it...]. What is the process?
13
votes
3answers
518 views

When does `ls -s` print “0”

Of course, the standard way of testing if a file is empty is with test -s FILE, but one of our clients have received a script containing tests like this: RETVAL=`ls -s ./log/cr_trig.log | awk '{print ...
4
votes
1answer
502 views

What filesystem has best support for shrinking?

Most mainstream filesystems can be grown fairly reliably, but what if I think I would like to shrink in future? XFS is a non runner. Reiser seems to have good support but gives scary BETA warnings , ...
2
votes
1answer
12k views

Changing user and group ID system wide (including file system attributes)?

(this question possibly related to Linux: simulating/masking user ownership upon mount of 'external' partitions? - Stack Overflow) I typically use Ubuntu (currently 11.04) as my desktop OS; let's say ...
2
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2answers
2k views

How to create a new partition in Ubuntu

I want to build my own Linux as "Linux From Scratch". I need to get a new partition from my hard disk. I checked and saw I have sda1. (I have about 20G empty) When I use the fdisk command n, I can ...
1
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1answer
1k views

Mount a Rackspace drive in Linux

Is there any software that will allow me to mount a Rackspace drive in linux? I want to copy SQL files from my database onto my Rackspace. I have web min running a backup nightly and copying those ...
6
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1answer
3k views

How does the Unix “fsck” differ from the Windows “chkdsk”?

What are the differences between Unix's fsck and Windows' chkdsk?
7
votes
2answers
5k views

mount freebsd slice partition under linux

I have under linux: Device Boot Start End Blocks Id System /filename.img * 63 1007999 503968+ a5 FreeBsd Under above partition i have two ...
2
votes
3answers
8k views

What is metadata, and how does it aid in the “fsck” process?

If I understand it correctly, "fsck" is used in UNIX systems to check for internal consistency within disks after there has been a crash. I was wondering, then, how it uses "metadata" to make sure ...
1
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1answer
974 views

Switching runlevel when moving /var to another partition

I'm running Ubuntu 10.04 and I would like to move /var to another partition using a python script. I found some directions that I thought were pretty good, but they call for switching to runlevel 1 ...
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2answers
564 views

Is there file format for checksums?

I want to store SHA512 checksum of the file for my application. How to do it in common (popular) way? So this checksum can be used but by third party application too.
12
votes
3answers
631 views

Symlink to part of the file?

Is there possible to create file that is just a sub-sequence of bytes from another file, like a symlink, but referencing only part of the file?
6
votes
4answers
3k views

mount ramfs as user

My fstab entry: none /home/jreinhart/ramdisk ramfs defaults,user 0 0 The directory before mounting: drwxrwxr-x 2 jreinhart jreinhart 4096 Oct 17 11:31 ramdisk The directory after ...
41
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2answers
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Why is '.' a hard link in Unix?

I've seen many explanations for why the link count for an empty directory in Unix based OSes is 2 instead of 1. They all say that it's because of the '.' directory, which every directory has pointing ...
2
votes
1answer
881 views

Running a command when a CD/DVD/BD inserted

This seems like a simple question to me, but after two nights of searching and tinkering, I haven't been able to find anything promising. I am running a headless Ubuntu server. I want to be able to ...
2
votes
3answers
348 views

What is the recommended filesystem to use when reaching sizes of 50TB?

My initial google searches say XFS or ReiserFS, but what does the community have to say about this? What are your experiences with 50TB sizes and up? Edit: After inquiring on IRC I think I would ...
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6answers
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Script to check for read only filesystem

How can I check a bunch of systems to find any filesystem that are mounted read-only? Possibly via a script?
86
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6answers
29k views

Why are hard links to directories not allowed in UNIX/Linux?

I read in text books that Unix/Linux doesn't allow hard links to directories but does allow soft links. Is it because, when we have cycles and if we create hard links, and after some time we delete ...
3
votes
1answer
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Ubuntu 11.04 and large external drives

I have a Hitachi USB external 3 terabyte drive attached to a Dell Precision T1500. When connected to the computer running Ubuntu 11.04 (2.6.38-11-generic #50-Ubuntu SMP Mon Sep 12 21:17:25 UTC 2011 ...
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2answers
366 views

Copying linux install from non-RAID/x86 to RAID/x86-64

I'm copying an Ubuntu Server install from an x86 machine with a single hard disk to a new machine with x64 and two identical disks. Two partitions will span the new disks: One small-ish RAID1 for ...
3
votes
1answer
1k views

Warnings about read-only filesystems while installing a solaris package

I have a solaris machine that I am trying to install Perl 5.12 as well as gcc and make to get CPAN working. I downloaded the packages from sun freeware, and was able to install gcc. When I tried to ...
11
votes
3answers
4k views

How can I determine the fs type of my current working directory?

I need a platform-independent and lightweight way of detecting the mount type of my CWD. Specifically, I need to determine if my CWD is in an SSHFS, NFS, CIFS, SMB, or local block store mount. I need ...
5
votes
2answers
3k views

/dev/sda2 has gone 49710 days without being checked, check forced

Why the shell show "/dev/sda2 has gone 49710 days without being checked, check forced." at centos start and then reboot? ...... /dev/sda2: Superblock last mount time is in the future. FIXED. ...
2
votes
2answers
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A command to check file access permission for another user

I need to know how to check the effective file access permissions for a given user, but it takes long to do this manually starting from / up to the target file or directory, checking group, ...etc.
5
votes
1answer
5k views

Is the file table in the filesystem or in memory?

In the context of operating system control tables, does the term "file tables" refer to a data structure that is part of the filesystem, or that is in main memory (and in which case I assume it would ...
14
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5answers
583 views

Which application should I blame for compulsively creating a directory again and again?

There's an application on my system which keeps creating an empty ~/Desktop directory again and again. I can't stand capital letters in my home, nor I can stand this “desktop” thingy. So, as picky as ...
4
votes
1answer
119 views

What is the proper way of sharing the /usr subdirectory?

What parts of the /usr subdirectory are usually shared in common practice without introducing any system instabilities? My intent is to share share-able parts of the /usr subdirectory among VM's of ...
19
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2answers
9k views

How can I find the number of files on a filesystem?

I want to know how many files I have on my filesystem. I know I can do something like this: find / -type f | wc -l This seems highly inefficient. What I'd really like is to do is find the total ...