A hard link is file system entry that associates a name with another file on a file system.

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11
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5answers
699 views

Why are hard links only valid within the same filesystem?

I am reading this intro to the command line by Mark Bates. In the first chapter, he mentions that hard links cannot span file systems. An important thing to note about hard links is that they ...
-1
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2answers
46 views

rsync --link-dest not working as expected with symlinks

I'm using rsync to backup some of my files: rsync -aEN --delete --link-dest="$CURR/" "$SOURCE/" "$NEW/" The --link-dest option works fine with most files, but not with symlinks. When I was writing a ...
1
vote
1answer
48 views

Extract hard link files with tar

I am trying to get list of all files in tar folder show them all on a page with links to download files. On click on single files it will be downloaded. This all is working fine except the hard link ...
2
votes
2answers
63 views

What is the best way to unlink hard-linked files?

Using rdfind I found a lot of hard-linked files (~60-90) and I want to unlink all of them. One possible solution is to just find all files -link +1 and just copy them, delete them and move it back to ...
2
votes
4answers
56 views

How to delete all duplicate hardlinks to a file?

I've got a directory tree created by rsnapshot, which contains multiple snapshots of the same directory structure with all identical files replaced by hardlinks. I would like to delete all those ...
3
votes
1answer
52 views

Deleting hardlink with rm -rfv deletes the original?

I was reading up on similar questions on here about what happens when you delete a hardlink to a file and the majority of the answers I was getting were that the hardlink is deleted but the original ...
2
votes
0answers
24 views

Creating an Arch ISO image produces invalid cross-device link errors

I have been trying to create a custom Arch ISO by following the archiso article at The ArchWiki, unfortunately whenever I run ./build.sh -v from my ~/archlive directory I get one of two types of error....
1
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2answers
55 views

find all hard linked files between two directories

How do I find if any files among two or more directories are hard linked? In other words, do any files under two or more directories refer to the same file? Similar to How to find all hard links to ...
0
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0answers
11 views

Difference between symlimk and link? [duplicate]

What is the difference between a "symlink" and a "link".
0
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0answers
27 views

File and folder size using ls and du [duplicate]

I created a folder and copied a 992 byte jpg file in it. Then I created a hard and soft links for the file. The hard link is the same size of the file and the soft link is 8 bytes. Now when I checked ...
10
votes
2answers
158 views

Are there any filesystems for which `ln -d` succeeds?

From the manpage for ln: -d, -F, --directory allow the superuser to attempt to hard link directories (note: will probably fail due to system restrictions, even for the superuser) Are there any ...
-1
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1answer
29 views

copying a file to a new directory, does this just create a new hardlink?

I am attempting to grasp hardlinks. When one copys a file from /dir1/file1 to /dir2/file1 does this create a hardlink, or is the data actually duplicated and now two hardlinks exist?
4
votes
1answer
51 views

Is there a tool to create a hard link to an unlinked inode?

Assume you have a filename/directory name, whatever, which is hard linked to inode 6400. Alas, the file/directory actually exists (completely intact, and maybe it only lives in a single data block, ...
4
votes
1answer
61 views

unpacking tarball with hard links on a file system that doesn't support hard links

I got a tarball (let's say t.tar.gz) that contains the following files ./a/a.txt ./b/b.txt where ./b/b.txt is a hard link to ./a/a.txt. I want to unpack the tarball on a network file system (AFS) ...
2
votes
0answers
38 views

Space efficiency of Btrfs reflinks vs hardlinks

A webpage referenced by the Wikipedia article on Btrfs claims that (emphasis mine) [Btrfs] reflinks have the same use as hardlinks, but are more space efficient. I thought that the opposite was ...
1
vote
2answers
31 views

How are hard links counted in UNIX? [duplicate]

When we create a directory in UNIX it has 2 hard links: . and ... One to itself and another one to its parent directory. As I read the . increases counter of the directory, and the .. increases hard ...
2
votes
1answer
42 views

Editing a file with several hard links

Let's say I have two hard links pointing at the same picture. /photography/picture_1.jpg /best_pictures/picture_1.jpg What happens if I edit /photography/picture_1.jpg? Is the hard link broken and ...
0
votes
2answers
42 views

Does soft linking a directory hard link its subfiles?

Suppose I have the following configuration: Folder A file1 file2 I then create a soft link of Folder A as follows: ln -s A B so that we now have: Folder A file1 file2 Folder B ( symlink of ...
2
votes
2answers
43 views

link to an executable and remove some parameters

I currently am using Xamarin Studio, which has a bug in this version. It adds 2 parameters to an executable, which causes the output to flood with error messages, slowing down the build time from a ...
1
vote
1answer
75 views

What link should i use for home- & owncloud-data?

the plan is to built a debian-based sever with owncloud for syncing addressbooks, calendars, files etc. and also access large video-files in the LAN via webdav from some kodi-clients (maybe also use ...
16
votes
2answers
912 views

Do hard links count as normal files?

I was wondering if there was a way to register this, but since most modern search engines don't work well with phrases over about 5 words in length, I need some help on this one. I was wondering ...
2
votes
2answers
159 views

Hard-link creation - Permissions?

Which permissions affect hard-link creation? Does file ownership itself matters? Suppose user alice wants to create a hard-link to the file target.txt in a directory target-dir. Which permissions ...
0
votes
3answers
192 views

Why wont my hard links update each other?

I am using Mac OS X, but the command line. I want to make a link from my .profile file, to another file on my system so that updating one updates the other and vice versa. This article makes me ...
3
votes
1answer
66 views

Why can't a UID 0 process hardlink to SUID files in a user namespace?

Consider the following transcript of a user-namespaced shell running with root privileges (UID 0 within the namespace, unprivileged outside): # cat /proc/$$/status | grep CapEff CapEff: ...
1
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2answers
111 views

Two hard linked files share inode

I'm working on an assignment for my college course, and one of the questions asks for the command used to create a hard link from one file to another so that they point to the same inode. We were ...
20
votes
4answers
1k views

Surprised by behavior of cp with hardlinks

I understand the notion of hardlinks very well, and have read the man pages for basic tools like cp --- and even the recent POSIX specs --- a number of times. Still I was surprised to observe the ...
1
vote
1answer
54 views

Should I use hardlinks for my “sites-enabled” folder instead of softlinks?

Every article I find about web servers suggest creating a sites-available and sites-enabled directory within apache/nginx/etc. Then, using symbolic (soft) links, create a link from the available to ...
2
votes
2answers
83 views

Can files with different inum be hard linked?

I am a new Linux user learning from Arch Linux and recently Linux From Scratch (7.7). I set up a new installation of AL to be my LFS host; I manually (and also with the provided bash script) checked ...
3
votes
1answer
137 views

How does `lsof` keep track of open file descriptors' filenames?

I've noticed, if a file is renamed, lsof displays the new name. To test it out, created a python script: #!/bin/python import time f = open('foo.txt', 'w') while True: time.sleep(1) Saw that ...
3
votes
1answer
92 views

hardlinks seem to take several hundred bytes just for the link itself (not file data)

Additional Info Firstly, thank you for all the answers. So I re-ran the tests again to test the answer below that a directory/folder entry takes up 4KB and this was skewing my numbers, so this time ...
-2
votes
1answer
96 views

Create five copies of file with the same inode number

How can I create five copies of /etc/profile with the same inode number?
5
votes
2answers
201 views

What is the difference in file size between Symbolic and Hard links?

I plan to keep all my movies in one giant folder, and then create other folders for the genres, while creating links for all the movies in the genre folder. This way I can organize movies into ...
5
votes
1answer
1k views

Hard link permissions behavior different between CentOS 6 and CentOS 7

I'm getting a permissions error in CentOS 7 when I try to create a hard link. With the same permissions set in CentOS 6 I do not get the error. The issue centers on group permissions. I'm not sure ...
17
votes
1answer
330 views

dpkg replacing files on a FAT filesystem

When you upgrade or reinstall a package with dpkg (and ultimately anything that uses it, like apt-get etc) it backs up the existing files by creating a hard link to the file before replacing it. That ...
2
votes
1answer
82 views

Generate SFV file, optimizing hard links

I'm currently running cfv -C -rr to generate a SFV file that contains the CRC32 checksums of all files in all subdirectories. The issue is that because there are so many hardlinks, this process is ...
14
votes
3answers
3k views

How to copy a directory recursively using hardlinks for each file

I want to create a "copy" of a directory tree where each file is a hardlink to the original file Example: I have a directory structure: dirA/ dirA/file1 dirA/x/ dirA/x/file2 dirA/y/ dirA/y/file3 ...
5
votes
1answer
493 views

Is it possible to create a non-empty file without write_close and rename event?

The reason why I am asking is because I'm using iwatch (not to confuse with a gadget device) to watch for filesystem events (in my case - file creation/renaming). What I cannot explain is this log: /...
3
votes
2answers
106 views

Several hard-links with different metadata in Linux using Ext4

Is it possible for Ext4 file systems (or maybe another one understood by Linux) to assign different metadata (like modification time, owner, access rights) to several hard-links that refer to the same ...
1
vote
1answer
64 views

Why does looking for hardlinks fail?

Here is how I find hard links located in /tmp: $ for file in /tmp/*; do if [ "$(stat -c %h -- "$file")" -gt 1 ]; then ls "$file" -l ; fi; done total 0 srwxrwxr-x 1 t t 0 Mar 20 23:01 debconf.socket ...
0
votes
1answer
824 views

Links in /usr/bin or /usr/local/bin: hard or symbolic?

For the links located in /usr/bin and in /usr/local/bin, are they better to be hard or symbolic? They seem to be all symbolic? Why?
0
votes
1answer
42 views

. as a command line argument to a command running in background

I run grep some-string -r . &. While it is running in bkg, I cd to another directory. It seems that grep interprets the hard link . differently then. What happens before and after I change the ...
1
vote
1answer
87 views

What operations raise link count

I had an interview, where the interviewer asked what operations raise the link count of a file, besides ln and its underlying syscall, I didn't know. He stated that opening a file will increase the ...
0
votes
2answers
53 views

How to specify the file type in a hard link [closed]

Does anyone know how to specify the file type of a hard link? Is this even possible? For example, I want to link to an HTML file (with content type text/html) in my website directory, so I used ln ...
2
votes
1answer
73 views

Can a hard link break the file system structure?

I want a very simple example of how can a hard link break the file system structure. I saw somewhere that people say it's because of loops, however, I can make a loop with a soft link and so I still ...
3
votes
1answer
578 views

rsync's --link-dest option does not link because of file time

Consider this test case: mkdir a echo 'blah' > a/test mkdir b echo 'blah' > b/test rsync -r --link-dest=/tmp/b /tmp/a/ /tmp/c As expected, rsync creates c/test a hardlink of b/test (note the ...
2
votes
0answers
274 views

Directory symlink to inode, not path (e.g. directory hardlinks)

I'm trying to better understand why directory hardlinks are not possible. Roughly, I think of directories and files as follows: directory --------- inode # exposed as . inode_of_parent # ...
2
votes
1answer
934 views

Hard Linking Other Users' Files

Suppose User A and User B have disk quotas of 1 GB. Also suppose User B creates a 900 MB file with permission 0666. This allows User A to access that file temporarily (for some project, etc.). Notice ...
2
votes
3answers
704 views

Convert a hardlink into a symbolic link

It is easy to convert a symlink into a hardlink with ln -f (example) It would also be easy to convert a hardlink (filenames link and original) back to a symbolic link to link->original in the case ...
0
votes
2answers
263 views

Change file hard link count

On my Linux machine, I have the following file: drwxr-xr-x 2 jsgdr Unix_31 4096 Dec 2 17:46 jsgdr How to change the permission 2 to 4 so that I will this: drwxr-xr-x 4 jsgdr ...
0
votes
1answer
145 views

Determine a file with the most Hard-Links

i got a homework today. Can u help me guys? "Determine on any PC pool that hosts regular file on the local file system root who has the most hard links! Avoid doing a search of the user home ...