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

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Why are there so many different ways to measure disk usage?

When I sum up the sizes of my files, I get one figure. If I run du, I get another figure. If I run du on all the files on my partition, it doesn't match what df claims is used. Why are there so many ...
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Reserved space for root on a filesystem - why?

I understand that by default, newly created filesystems will be created with 5% of the space allocated for root. I also know you can change the defined space with: tune2fs -m 1 /dev/sdXY What I'm ...
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What mount points exist on a typical Linux system?

I have 2 questions. During Linux installation we specify memory space for 2 mount points - root and swap. Are there any other mount points created without the users notice? Is this statement ...
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ext4: How to account for the filesystem space?

I've recently formated a 1.5 TB drive with the intention of replacing ntfs with ext4. Then I noticed that the files I saved don't fit on the new partition. df: ext4 (ext3 & ext2 show the same ...
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What is a Superblock, Inode, Dentry and a File?

From the article Anatomy of Linux File Systems by Tim Jones, I read that Linux views all the file systems from the perspective of a common set of objects and these objects are superblock, inode, ...
14
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The merits of a partitionless filesystem

I ran into something a couple of weeks ago that I'd never seen before: A filesystem (ext3 I believe) installed to a storage device without a partition. In essence /dev/sdb was the entire filesystem. I ...
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Find filesystem of an unmounted partition from a script

I'm writing a custom automated install using AIF (Arch Installation Framework), and I need to find the filesystem on a partition given a partition. So far I have this: grok_partitions () { local ...
20
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Where do the files go if you mount a drive to a folder that already contains files?

I just accidentally mounted a new drive to a folder that already contained files. I don't care about them and have them somewhere else, but that folder appears empty now. I'm curious what happened ...
119
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/usr/bin vs /usr/local/bin on Linux

Why are there so many places to put a binary in Linux? There are atleast these five: /bin/ /sbin/ /usr/bin/ /usr/local/bin/ /usr/local/sbin/ And on my office box, I do not have write permissions ...
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Why do hard links exist?

I know what hard links are, but why would I use them? What is the utility of a hard link?
4
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4answers
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How to recover a file just deleted [duplicate]

I just deleted a file in Nautilus with Shift+Delete, which warned me that "If you delete an item, it will be permanently lost." I wonder if there is no way to recover the file? My OS is Ubuntu 10.10. ...
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6answers
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Why hard links not allowed to directories in UNIX/Linux

I read in text books that UNIX/Linux doesn't allows hard links to directories but soft links do. Is it because, when we have cycles and if we create hardlinks, and after some time we delete the ...
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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 ...
18
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8answers
992 views

How to tell what type of filesystem you're on?

Is there a command to tell what type of filesystem you're using?
21
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1answer
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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% ...
5
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2answers
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How to show the filesystem type via the terminal? [duplicate]

Possible Duplicate: How to tell what type of filesystem you’re on? Find filesystem of an unmounted partition from a script How can I quickly check the filesystem of the partition? Can I ...
253
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3answers
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What is the purpose of the lost+found folder in Linux and Unix?

There is a folder at the root of Linux and Unix operating systems called /lost+found/ What is it for? Under what circumstances would I interact with it? How would I interact with it?
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timestamp, modification time, and created time of a file

I just know that ls -t and ls -f give different sorting of files and subdirectories under a directory. What are the differences between timestamp, modification time, and created time of a file? How ...
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3answers
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Why does '/' have an '..' entry?

This just baffles me. Why does the root directory contain a reference to a parent directory? bob@bob:/$ ls -a . build home lib32 mnt .rpmdb sys vmlinuz .. cdrom ...
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4answers
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Clear unused space with zeros (ext3,ext4)

How to clear unused space with zeros ? (ext3,ext4) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like FSArchiver is looking for "used space" ...
12
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5answers
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How can I copy a file and create the target directories at the same time?

I want to cp aaa/deep/sea/blob.psd to bbb/deep/sea/blob.psd How do I do the copy if the deep and sea directories don't exist under bbb so that the copy both creates the directories that are needed ...
12
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3answers
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On system memory… specifically the difference between `tmpfs,` `shm,` and `hugepages…`

I've been curious lately about the various Linux kernel memory based filesystems. Note: As far as I'm concerned, the questions below should be considered more or less optional when compared with a ...
5
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2answers
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mount options shown in /proc/mounts

IIRC then the mount options shown in /proc/mounts have changed. Some time ago acl and user_xattr were shown, now it seems that only noacl and nouser_xattr are shown if these features are turned off. ...
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What file systems on Linux store the creation time?

Are there any (good known, reliable) file systems on Linux that store the creation time of files and directories in the i-node table? If there are, is the "changed" time replaced by the creation ...
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2answers
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How to repair a corrupted HFS+ partition from a damaged hard-disk?

I have a friend's Mac OS X disk that comes with an HFS+ partition. I am supposed to recover the personal data from this disk, and I'm not yet sure if the filesystem is corrupted or the disk is dying). ...
5
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3answers
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How can I edit symlinks?

My basic understanding of a symlink is as a special file, a file that contains a string path to another file. The kernel's VFS abstracts a lot of that away but is there any reason why symlinks seem to ...
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Format external hard drive to linux compatible file system

How do I format my external hard drive to a very Linux compatible file system?
47
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5answers
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Can I configure my Linux system for more aggressive file system caching?

I am neither concerned about RAM usage (as I've got enough) nor about losing data in case of an accidental shut-down (as my power is backed, the system is reliable and the data are not critical). But ...
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2answers
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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 ...
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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 ...
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Birth is empty on ext4

I was just reading up on the Birth section of stat and it appears ext4 should support it, but even a file I just created leaves it empty. ~ % touch test ...
14
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1answer
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What is Linux doing differently that allows me to remove/replace files where Windows would complain the file is currently in use?

The example I have is Minecraft. When running Bukkit on Linux I can remove or update the .jar files in the /plugins folder and simply run the 'reload' command. In Windows, I have to take the whole ...
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How does the sticky bit work?

SUID The sticky bit applied to executable programs flagging the system to keep an image of the program in memory after the program finished running. But I don't know that what it's stored in ...
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ZFS under Linux, does it work?

Could I get ZFS to work properly in Linux? Are there any caveats / limitations?
23
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Recovering ext4 superblocks

Recently, my external hard drive enclosure failed (the hard drive itself powers up in another enclosure). However, as a result, it appears its EXT4 file system is corrupt. The drive has a single ...
14
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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?
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How to clean up unnecessary files

Please suggest me any particular unnecessary file that I can clean to back everything to normal condition(temporarily). (i.e. any log or archieve or anything ). My var/log has only 40MB and Home ...
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1answer
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When was `relatime` made the default?

What is the first Linux kernel release to set relatime as the default mount option?
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Mount Google Drive in Linux?

Now that Google Drive is available, how do we mount it to a Linux filesystem? Similar solutions exist for Amazon S3 and Rackspace Cloud Files.
25
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1answer
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How to determine the filesystem of an unmounted device? [duplicate]

Possible Duplicate: Find filesystem of a partition from a script How to show the filesystem type via the terminal? I'm looking for a command that yields the filesystem type as mount would ...
17
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4answers
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File system for an SSD drive

I always thought that traditional file systems, are geared and optimized for non-ssd drive, where, for instance, data locality is important, and fragmentation is problematic. Is there a file system ...
13
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1answer
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Number of files per directory

I have a directory with about 100000 small files (each file is from 1-3 lines, each file is a text file). In size the directory isn't very big (< 2GB). This data lives in a professionally ...
18
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7answers
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Linux equivalent to ReadyBoost?

Is there a kernel module or some other patch or something similar to Windows' ReadyBoost? Basically I'm looking for something that allows disk reads to be cached on a Flash drive.
13
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2answers
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How can I be sure that a directory or file is actually deleted?

I know that most files, when deleted, aren't actually removed from the disk, and can be recovered later. How can I ensure that a directory I had deleted will actually be removed from the disk? Are ...
10
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1answer
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Difference between block size and cluster size

I've got a question concerning the block size and cluster size. Regarding to what I have read about that I assume the following: The block size is the physical size of a block, mostly 512 bytes. ...
2
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1answer
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what are the different ways to set file permissions etc on gnu/linux

On Unix a long time back I learned about chmod to set permissions and to allow programs to gain privileges. I have recently discovered extra commands on GNU/Linux: chattr, setfacl, setcap. Are there ...
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2answers
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understanding “mount” as a concept in the OS

I want to understand what mounting is. It is used in different contexts and situations and I can't find resources which: Describe the mount concept Explain the actions taken by the ...
10
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4answers
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What is the “directory order” of files in a directory (used by `ls -U`)?

According to the man page for ls, ls -U means: do not sort; list entries in directory order. What does "directory order" mean, and how is it determined? The following test (executed on an ...
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Several questions about file-system character encoding on linux

Due to a lot of file exchange works between Windows (GBK encoding) and Linux (UTF-8 encoding), it will encounter character encoding issues easily, such as: zip/tar files whose name contains chinese ...
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2answers
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Best options for mounting Mac OS X hard drive on my Linux box?

I have a new 3 terabyte external USB hard drive (Seagate ST3000DM001 in an enclosure). I hope to use it on both my iMac (OS X 10.6.8) and my Linux machines (Kubuntu). Right now this drive will ...