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I can understand the rationale of hiding files and folders in the /home/user directory to prevent users from messing around with things. However, I do not see how the same rationale can be applied to files in the /etc, /boot and /var directories which is the domain of administrators.

My question is why are some files and folders hidden from administrators? Example:

/boot/.vmlinuz-3.11.1-200.fc20.x86_64.hmac
/etc/.pwd.lock
/etc/selinux/targeted/.policy.sha512
/etc/.java
/etc/.java/.systemPrefs
/etc/skel/.bash_profile
/root/.ssh
/root/.config
/var/cache/yum/x86_64/20/.gpgkeyschecked.yum
/var/spool/at/.SEQ
/var/lib/pear/.filemap
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look the second answer. The reason for those files you listed are either they are config files which should not be changed daily and are always present as .ssh and .bash_profile so you don't wanna know they are there.It is just a convention. Files at spool are temp files same as many of the others you listed so they should not be edited manually hence they are hidden –  vfbsilva Aug 1 at 13:36
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.ssh and .config are always named that, whether they're in a normal user's home directory or the root user's home directory. /etc/skel is supposed to be a prototype for new users' home directories, and the files have the same names there as they will in the newly-created directories. –  Mark Plotnick Aug 1 at 13:49
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But those files are not hidden. The ls command just doesn't list files beginning with a dot by default(see info ls) - it's the design of this particular piece of software. –  Amphiteót Aug 1 at 14:24
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@illuminÉ: So how exactly would you define "hidden" if not as "not shown by default"? Note that this is not a property just of ls; also shell expansion of globs will not include those files unless the leading dot is explicitly included in the pattern, and usually file managers will not show them unless you choose the option "Show hidden files" (yes, the option does use that term). –  celtschk Aug 2 at 12:10

3 Answers 3

up vote 11 down vote accepted

You've misinterpreted the primary rationale for "hidden files". It is not

to prevent users from messing around with things.

Although it may have this consequence for very new users until they learn what a "dot file" is (dot file and dot directory are perhaps more appropriate and specific terms than "hidden"). All by itself it doesn't prevent you from messing around with things -- that's what permissions are for. It does perhaps help to indicate to new users that this is something they should not mess around with until they understand what it is for.

You could thus think of the dot prefix as a sort of file suffix -- notice they usually don't have one of those, although they can. It indicates this file is not of interest for general browsing, which is why ls and file browsers usually will not display it. However, since it's a prefix instead of a suffix, there is the added bonus, when you do display them (ls -a) in lexicographical order, to see them all listed together.

The normal purpose of a file like this is for use by an application (e.g. configuration). You don't have to use them directly or even be aware of them.

So, this "hiding" isn't so much intended to literally hide the file from the user as it is to reduce clutter and provide some organization conceptually.

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Thanks for your answer. Does it imply that these files are of lesser significance and hence are hidden to reduce clutter? –  Question Overflow Aug 1 at 14:16
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I guess that depends on your perspective. It does say something about what the significance of the file (likely) is. They're used in home directories for per user configurations, but they're also used in directories generally to indicate per directory configuration. Two examples: Version control systems such as git will use them; when git scans a given directory, if there is a .gitignore file present, it will read it; and when you start gdb, it will read a $PWD/.gdbinit file if present (and a ~/.gdbinit; another common method). –  goldilocks Aug 1 at 14:32

This might be a highly opiniated answer, but I think the main reason dot files and dot directories are marked like that is not to hide or obscure them - I think it's just to let the user know that within those files and directories are program's and user's settings that can be changed by them or by the programs themselves.

The fact that dot files and dot directories are omitted by default by the command line ls and from the views in most file managers is just a commodity - you don't want to show the internal/details for everything, unless requested by the user; if the user wants to change a setting, and he/she can't do it through a GUI, then is very likely to find the setting he/she is looking for in a dot files.

e.g.> inside $HOME/.vimrc you will find the config setting for vim.

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/etc/skel contains files to be copied to new user's home directories, therefore the names are, of course, the same as in an user's home directory. This explains /etc/skel/.bash_profile. The directory /root also is a home directory, namely the home directory of the user root. This explains /root/.ssh and /root/.config.

/etc/.pwd.lock seems to be a lock file. You normally are not interested in lock files, therefore it makes sense for it to be hidden.

For the other files, I don't know what they are for, but I'm sure there's also a good explanation why they are hidden.

And of course goldilocks is right that dotfiles are hidden not in order to prevent anyone to mess with them (the basic idea of Unix is to assume that the user knows what he does), but in order to prevent them cluttering up your directory listings (although for configuration files in the home directory I would have considered an etc subdirectory a better solution).

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