A file system structure in which to store computer files.

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202
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3answers
108k views

How do directory permissions in Linux work?

In my CMS, I noticed that directories need the executable bit (+x) set for the user to open them. Why is the execute permission required to read a directory, and how do directory permissions in Linux ...
70
votes
6answers
12k views

How does Linux handle multiple consecutive path separators (/home////username///file)?

I'm working on a python script that passes file locations to an scp subprocess. That's all fine, but I'm in a situation where I may end up concatenating a path with a filename such that there's a ...
55
votes
7answers
20k views

The result of ls * , ls ** and ls ***

I know using the command ls will list all the directories. But what does the ls * command do ? I used it and it just lists the directories. Is the star in front of ls means how deep it can list the ...
12
votes
4answers
5k views

How to run a command when a directory's contents are updated?

There is a directory A whose contents are changed frequently by other people. I have made a personal directory B where I keep all the files that have ever been in A. Currently I just occasionally ...
39
votes
4answers
9k views

What does size of a directory mean in output of 'ls -l' command?

What does size of a directory mean in output of ls -l command?
127
votes
1answer
162k views

How to set default file permissions for all folders/files in a directory?

I want to set a folder such that anything created within it (directories, files) inherit default permissions and group. Lets call the group "media". And also, the folders/files created within the ...
21
votes
8answers
4k views

Any way to sync directory structure when the files are already on both sides?

I have two drives with the same files, but the directory structure is totally different. Is there any way to 'move' all the files on the destination side so that they match the structure of the ...
26
votes
2answers
6k views

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 ...
54
votes
2answers
38k views

Do the parent directory's permissions matter when accessing a subdirectory?

If I have a root folder with some restrictive permission, let's say 600, and if the child folders/files have 777 permission will everybody be able to read/write/execute the child file even though the ...
91
votes
7answers
31k 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 ...
40
votes
5answers
72k 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 ...
25
votes
3answers
11k views

When should I use a trailing slash on a directory? [duplicate]

Possible Duplicate: How linux handles multiple path separators (/home////username///file) Most commands I use in linux behave exactly the same whether I include the trailing slash / ...
39
votes
4answers
16k views

How to remove all empty directories in a subtree?

How can I remove all empty directories in a subtree? I used something like find . -type d -exec rmdir {} 2>/dev/null \; but I needs to be run multiple times in order to remove directories ...
24
votes
1answer
440 views

When did directories stop being readable as files?

I have the 1st edition of The Unix Programming Environment book. In chapter 2, the authors state that directories are readable as files, and mention some facts about the format of these files. They ...
47
votes
7answers
18k views

What does the .d stand for in directory names?

I know many directories with .d in their name: init.d yum.repos.d conf.d Does it mean directory? If yes, from what does this disambiguate? UPDATE: I've had many interesting answers about what the ...
8
votes
7answers
12k views

What's the best way to count the number of files in a directory?

If parsing the output of ls is dangerous because it can break on some funky characters (spaces, \n, ... ), what's the best way to know the number of files in a directory? I usualy rely on find to ...
7
votes
4answers
235 views

List all directories that do NOT have a file with a given file name inside

How would I go into listing all directories that do not have a file with a given file name inside? e.g. given this tree / /a README file001 file002 /b README file001 /c ...
25
votes
2answers
44k views

Getting new files to inherit group permissions on Linux

I am having a problem with permissions on a Linux server. I am used to BSD. When a directory is owned by a group the user who owns it isn't in such as www-data, files created in it will be owned by ...
10
votes
2answers
7k views

Why does a new directory have a hard link count of 2 before anything is added to it?

Say I just create directory newDirectory and then I do ls -ld command. I see that the number of hard links is 2. What exactly makes the hard link 2 from the start? Also is the number of subdirectories ...
12
votes
1answer
2k views

How to find all the links to a directory

When I stat a directory I get a listing that tell me there are 5 links to the directory. stat dir My question is how do I get information (names and locations) to all these 5 links?
61
votes
3answers
3k views

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 ...
25
votes
3answers
20k views

Is there any way to prevent deletion of certain files from user owned directory?

Let's say user has Directory1 and it contains File1 File2 CantBeDeletedFile How to make so the user would never be allowed to delete the CantBeDeletedFile? If I change the ownership of Directory1 and ...
14
votes
5answers
10k views

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 ...
6
votes
1answer
11k views

In Linux, “Write” Permission Is Equivalent To “Execute” For Directories?

The Execute permission makes sense for files (which include scripts etc), but when it comes to directories, write (w) permission works the same way as execute (x), right? Which means, if we are giving ...
3
votes
1answer
3k views

How can I make ls show information about the directory specified only, not info about its sub-files or folder contents?

Say I have folder "foo" residing, the home directory. I want to get some info of it, owner, group, permissions, etc... I then do this to try to get the information: cd ~ ls -l foo Of course it now ...
8
votes
3answers
563 views

“mkdir foo; svn mv * foo”

I often want to do some variant of this idiom: $ mkdir 2010 $ svn mv * 2010 Of course, I get an error because the glob matches 2010 as well: svn: Cannot copy path '2010' into its own child ...
55
votes
5answers
34k views

Difference between /bin and /usr/bin

I read this up on this website and it doesn't make sense. http://rcsg-gsir.imsb-dsgi.nrc-cnrc.gc.ca/documents/basic/node32.html When UNIX was first written, /bin and /usr/bin physically resided ...
49
votes
1answer
211k views

Create a symbolic link relative to the current directory

I'm trying to create a symbolic link in my home directory that points to a directory on my external HDD. It works fine when I specify it like this: cd ~ ln -s /run/media/name/exhdd/Data/ Data ...
69
votes
4answers
66k views

What is the 'working directory' when cron executes a job

I have a script that works when I run it from the command line, but when I schedule it with cron I get errors that it cannot find files or commands. My questions is twofold: When I schedule a cron ...
53
votes
8answers
45k views

Merging folders with mv?

If I use mv to move a folder called "folder" to a directory that already contains "folder" will they merge or will it be replaced?
41
votes
2answers
2k views

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 ...
29
votes
10answers
161k views

How to remove all the files in a directory?

I am trying to remove all files and subdirectories in a directory. I used rm -r to remove all files, but I want to remove all files and subdirectories, excluding the top directory itself. For ...
16
votes
3answers
15k views

How can I move files by type recursively from a directory and its sub-directories to another directory?

What would be a good way to move a file type from a directory and all of its sub-directories? Like "move all *.ogg in /thisdir recursively to /somedir". I tried a couple of things; my best effort was ...
13
votes
4answers
13k views

How can I force unzip / zip not to create a subdirectory when I extract it?

Depending on how a zip file is created, sometimes it will extract all of the files directly, and sometimes it will extract the files into a subdirectory. If the latter is true, how can I force the ...
9
votes
4answers
12k views

How do I change folder timestamps recursively to the newest file?

I was wondering if anyone knows how to change the timestamps of folders recursively based on the latest timestamp found of the files in that folder. So for example: ...
10
votes
3answers
1k views

Lowercasing all directories under a directory

I want to lowercase every directories' name under a directory. With which commands can I do that?
9
votes
4answers
7k views

How are directories implemented in Unix filesystems?

My question is how directories are implemented? I can believe a data structure like a variable e.g. table, array or similar. Since UNIX is Open Source I can look in the source what the program does ...
7
votes
4answers
3k views

What are the advantages of the Unix file system structure

If I install an application in Linux for example Debian/Gnu Linux, the files of the applications are copied to many different directories in the file system. Some scripts goes into /usr/share .. ...
4
votes
1answer
138 views

Fine-tune LS_COLORS for directory suffixes?

I’m fine customizing most settings in LS_COLORS. I don’t need help customizing the colors for different file suffixes. What I would like to do is configure special colors for certain directories, ...
4
votes
1answer
1k views

Write-only permission for a directory doesn't allow to rename (move) files inside?

In fact, I would like to ask more general question -- "what does write permission for a directory allow you to do exactly?" -- but let's approach it with a concrete example. It is a long question, if ...
2
votes
3answers
9k views

cp --no-target-directory explained

Question: I need a simple example of how to use cp --no-target-directory. I do experience some difficulties in understanding cp --no-target-directory. I do understand the explanation for mv ...
1
vote
1answer
129 views

What is the “~/” directory?

I'm trying to locate where some files are stored and I can easily browse to them via ssh by going to "cd ~/foldername", however, I have no idea what directory "~/" actually is. When I browse around ...
63
votes
10answers
68k views

How do I get the MD5 sum of a directory's contents as one sum?

The md5sum program does not provide checksums for directories. I want to get a single MD5 checksum for the entire contents of a directory, including files in sub-directories. That is, one combined ...
33
votes
4answers
141k views

“Input/output error” when accessing a directory

I want to list and remove the content of a directory on a removable hard drive. But I have experienced "Input/output error": $ rm pic -R rm: cannot remove `pic/60.jpg': Input/output error rm: cannot ...
37
votes
3answers
29k views

Why unix mv program doesn't need -R (recursive) option for directories but cp does need it?

This is a kind of "wtf?" question, so I'm sorry if I will disturb someone's vision of how things should be or if I will just annoy you with the "stupid" question. I always get messed up when need to ...
14
votes
7answers
51k views

Using sftp to Transfer a Directory?

When I try to use sftp to transfer a directory containing files, I get an error message: skipping non-regular file directory_name The directory contains a couple of files and two subdirectories. ...
27
votes
1answer
5k views

Why was '.' chosen to represent the current directory and '..' for parent directory?

After reading this question Design question: Why was '~' chosen to represent the home directory?, next obvious question on my mind was why '.' and '..' was used to represent current directory ...
9
votes
1answer
4k views

how to view a directory's permission

What is the command with which you can directly view the permission bits of a directory?
7
votes
2answers
9k views

Determine what device a directory is located on

If I do # cd / # ln -s /home test # cd test # mount --bind $PWD /mnt the entry in /proc/mounts is /dev/sda2 /mnt ext4 rw,noatime,data=ordered 0 0 which is the device that is mounted to /home and ...
6
votes
2answers
389 views

Folder with ONLY write permission is useless… right?

Having worked with Linux for years, and finding myself with some free time, I decided to revisit some basics. So I re-read the stuff about permissions (without checking source code), and its special ...