list of file owners in folder on linux
I have a folder with many files. The files have been created by many different users. I do not know about shell scripting. I need to get the list of the username (only) of the owners of the files. I may save the output of ls -l and then parse it using perl python etc. But how can i do this using shell scripting?
3 Answers 3
ls -l /some/dir/some/where | awk '' | sort | uniq which gets you a unique and sorted list of owners.
@DanielKamilKozar Perhaps it’s not odd, but if you allow whitespace in your system’s filenames, then there are bigger problems at hand.
to go through the directory recursively, add the R switch to the ls command: ls -lR /some/dir/some/where | awk ‘
People, people — this is what the find command is meant for. Try something like this: find /some/dir/some/where -execdir stat -c «%U» <> + | sort | uniq .
The two solutions so far are good, but have their limitations.
This should guarantee you properly and recursively search every file in a directory tree.
sudo find /some/dir/ -exec stat -c "%U" <> + | sort | uniq In other words, recursively search for files in /some/dir , and execute stat -c «%U» (print username) on the files, in as few invocations of stat as possible ( -exec <> + syntax), then of course sort the list of usernames, and in turn cull them to just the uniq ue set of usernames.
To limit the search to just regular files, then add the -type f clause:
sudo find /some/dir/ -type f -exec stat -c "%U" <> + | sort | uniq _______ Is there a command to list all users? Also to add, delete, modify users, in the terminal?
I need a command to list all users as well as commands to add, delete and modify users from terminal — any commands that could help in administrating user accounts easily by terminal.
10 Answers 10
To list
To list all local users you can use:
To list all users capable of authenticating (in some way), including non-local, see this reply.
Some more useful user-management commands (also limited to local users):
To add
To add a new user you can use:
sudo adduser new_usernamesudo useradd new_usernameTo remove/delete
To remove/delete a user, first you can use:
Then you may want to delete the home directory for the deleted user account :
Please use with caution the above command!
To modify
To modify the username of a user:
usermod -l new_username old_usernameTo change the password for a user:
To change the shell for a user:
To change the details for a user (for example real name):
To add a user to the sudo group:
And, of course, see also: man adduser , man useradd , man userdel . and so on.
Radu forgot to mention sudo chfn
I think that it should be underlined that the correct answer to the linked question is askubuntu.com/a/381646/16395 — otherwise you have to take into account the GID/UID Ubuntu policies by hand. The accepted answer is not so clear.
sudo userdel DOMAIN\\johndoe gives me the error: «userdel: cannot remove entry ‘DOMAIN\johndoe’ from /etc/passwd — I looked in /etc/passwd and they’re not even in there, likely because it’s a «domain» account?
@00fruX Yeah. If you’re using a centralised user database you’re going to need to deal with it directly.
Just press Ctrl + Alt + T on your keyboard to open Terminal. When it opens, run the command(s) below:
less /etc/passwd more /etc/passwd @nux A bit late to the party, but from command line use adduser instead, useradd should be limited to scripts where the author really really knows what he is doing.
The easiest way to get this kind of information is getent — see manpage for the getent command . While that command gives the same output as cat /etc/passwd it is useful to remember because it will give you lists of several elements in the OS.
To get a list of all users you type (as users are listed in /etc/passwd )
To add a user newuser to the system you would type
to create a user that has all default settings applied.
Bonus: To add any user (for instance anyuser) to a group (for instance cdrom) type
sudo adduser anyuser cdrom You delete a user (for instance obsolete) with
If you want to delete his home directory/mails as well you type
sudo deluser --remove-home obsolete sudo deluser --remove-all-files obsolete will remove the user and all files owned by this user on the whole system.
It’s useful to remember that getent doesn’t just print the output of users in /etc/passwd but all users in all configured userdb backends on a given system, whether it’s /etc/passwd or LDAP, etc.
@MarcinKaminski is right, it also prints users setup in SSO systems who have access to the server. this answer is the the best one, with getent passwd being the right command
This should get, under most normal situations, all normal (non-system, not weird, etc) users:
awk -F'[/:]' '= 1000 && $3 != 65534) print $1>' /etc/passwd - reading in from /etc/passwd
- using : as a delimiter
- if the third field (the User ID number) is larger than 1000 and not 65534, the first field (the username of the user) is printed.
This is because on many linux systems, usernames above 1000 are reserved for unprivileged (you could say normal) users. Some info on this here:
A user ID (UID) is a unique positive integer assigned by a Unix-like operating system to each user. Each user is identified to the system by its UID, and user names are generally used only as an interface for humans.
UIDs are stored, along with their corresponding user names and other user-specific information, in the /etc/passwd file.
The third field contains the UID, and the fourth field contains the group ID (GID), which by default is equal to the UID for all ordinary users.
In the Linux kernels 2.4 and above, UIDs are unsigned 32-bit integers that can represent values from zero to 4,294,967,296. However, it is advisable to use values only up to 65,534 in order to maintain compatibility with systems using older kernels or filesystems that can only accommodate 16-bit UIDs.
The UID of 0 has a special role: it is always the root account (i.e., the omnipotent administrative user). Although the user name can be changed on this account and additional accounts can be created with the same UID, neither action is wise from a security point of view.
The UID 65534 is commonly reserved for nobody, a user with no system privileges, as opposed to an ordinary (i.e., non-privileged) user. This UID is often used for individuals accessing the system remotely via FTP (file transfer protocol) or HTTP (hypertext transfer protocol).
UIDs 1 through 99 are traditionally reserved for special system users (sometimes called pseudo-users), such as wheel, daemon, lp, operator, news, mail, etc. These users are administrators who do not need total root powers, but who perform some administrative tasks and thus need more privileges than those given to ordinary users.
Some Linux distributions (i.e., versions) begin UIDs for non-privileged users at 100. Others, such as Red Hat, begin them at 500, and still others, such Debian, start them at 1000. Because of the differences among distributions, manual intervention can be necessary if multiple distributions are used in a network in an organization.
Also, it can be convenient to reserve a block of UIDs for local users, such as 1000 through 9999, and another block for remote users (i.e., users elsewhere on the network), such as 10000 to 65534. The important thing is to decide on a scheme and adhere to it.
Among the advantages of this practice of reserving blocks of numbers for particular types of users is that it makes it more convenient to search through system logs for suspicious user activity.
Contrary to popular belief, it is not necessary that each entry in the UID field be unique. However, non-unique UIDs can cause security problems, and thus UIDs should be kept unique across the entire organization. Likewise, recycling of UIDs from former users should be avoided for as long as possible.