Linux show file owner

Last updated on: 2019-03-07

Authored by: Jered Heeschen

This article explains how to use the ls command to check Linux® file permissions. Being able to check the permissions on a file is useful, especially for troubleshooting. You can ensure that a user can read a particular file, for example, or examine a directory structure to ensure that users can follow the hierarchy to the files that they need.

For a more in depth discussion on Linux file permissions, see Linux file permission concepts.

ls command

Use the ls command (the first letter is a lowercase L) to see what files are in a directory. When run by itself, ls returns a list of the current working directory. You can also specify a directory to list. The following example shows a list of the first few files in the /etc directory on a Gentoo system.

The -h option changes the way file sizes are displayed. When you use the -h option, files sizes are displayed in the human-readable format of kilobytes, megabytes, and so on, rather than in raw bytes. Other linux tools such as df also support this flag. The command df -h shows current disk usage in a easier to read format.

To display hidden files (files with names that start with a period), use the -a option. For example, if you use only ls to look at the root home directory on a clean Linux installation, no files are returned:

However, if you add the -a option, the ls command returns a list of files:

Files that start with a period are often system files and application settings files, and you usually don’t want them included in directory lists. But it’s important to know that they’re there and how to see them. The .bashrc file is especially useful to know about because it contains user environment settings that you can change.

If you combine the -a option with the -l option (see the next section) into -la , you get all the details of the hidden files:

Consider the single period and double period in both directory lists:

The single period (.) refers to the directory itself. This is convenient if you want it to run a command and reference your current directory (for example, when you want to copy a file there).

The double period (..) refers to the parent directory. If you type cd .. the directory changes to the one above the one you’re in, in the file system hierarchy. For example, if your current directory is /root , typing cd .. would take you to / , the very top of the hierarchy.

To get more information about the files in a directory, use the -l option with ls, as shown in the following example.

The file names are on the far right side of each line, and the file details precede the names. The necessary details to check file permissions are (1) the series of letters and dashes on the far left of each line, and (2) the two columns that have root in them (in the preceding example). The rest of this article explains how to interpret and use these details.

Permission details

This section explains the series of letters and dashes that define the file permissions.

The first character: file type

In the preceding examples, the first character in each list was either a dash (-) or the letter d .

A dash (-) indicates that the file is a regular file.

The letter d indicates that the file is a directory, which is basically a special kind of file.

A special file type that you might see is a symlink, sometimes called a soft link. It begins with a lowercase L , as shown in the following example:

A symlink is a pointer to another location in the file system.

Permissions abbreviations

Permissions for files are represented by the following letters.

r refers to the read permission.
w refers to the write permission.
x refers to the execute permission.

The permissions characters

Consider the following example:

The first trio of letters after the file type in a file list ( rwx ) shows the permissions for the user , or file owner.

The next trio of characters (also rwx ) shows the permissions for the group category.

The last trio of characters ( r-x ) shows the permissions for the final category, other . In this example, users who are neither the file owner nor in the group have read and execute permissions but not write, as indicated by the dash (-) in the middle position.

Notice the specific order to the permissions in a trio: read, write, execute. A dash in place of a letter for a permission means that category doesn’t have that permission.

The first number

The number listed after the permissions indicates the link count of a file or the number of contained directory entries, for a directory. This number is not relevant for permissions.

Owner and group

After the number of links, two names are listed. In the preceding example, the names are root and mail .

The first name indicates the owner of the file. The user permissions apply to the owner of the file, so in this case, the user ‘root’ has read, write, and execute permissions for this directory.

The second name is the file’s group. The group permissions apply to any user in the same group as the file, so in this case, those permissions apply to anyone in the mail group.

The rest

The remainder of the file details are the size of the file, the date and time that the file was created or last modified, and the file name.

Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License

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Linux / Unix Find All The Files Owned By a Particular User / Group

Let us see how to use the find command to locate all files/folders owned by one or many users on Linux or Unix-like system.

Find file owned by a group

Tutorial details
Difficulty level	Easy
Root privileges	Yes
Requirements	Linux or Unix
Est. reading time	2m

Use the following syntax to find files owned by users(s) in Linux/Unix:
find directory-location -group < group-name >-name < file-name >
Where,

directory-location : Locate the file in this directory path.
-group : Find the file belongs to group-name.
-name : The file name or a search pattern

In this example, locate or find all files belongs to a group called “ftpusers” in the /home directory:
# find /home -group ftpusers
To find all *.c file belongs to a group called “ftpusers” in /data/project directory, run:
# find /data/project -group ftpusers -name «*.c»
OR do case insensitive search:
# find /data/project -group ftpusers -iname «*.c»

Find all *.mp4 files by group vivek

Find file owned by user

The syntax is:
find directory-location -user < username >-name < file-name >
Where,

directory-location : Locate files or directories in this directory location.
-user < user-name >: Find the file belongs to user.
-name : File name or pattern.

In this example, locate or find all file belongs to a user called “vivek” in /var directory:
# find /var -user vivek
To find all *.pl (perl files) file belongs to a user called “vivek” in /var/www directory, enter:
# find /var/www -user vivek -name «*.pl»

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How to find files by users vivek and wendy

### match files only ##
# find / -type f -user vivek -o -user wendy
### match dirs only ##
# find / -type d -user vivek -o -user wendy

Conclusion

You just learned how to find all of the files created by a particular user/group and display them to the screen. For more info see find command man page.

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Chown Command: Change Owner of File in Linux

Home » SysAdmin » Chown Command: Change Owner of File in Linux

The chown command changes user ownership of a file, directory, or link in Linux. Every file is associated with an owning user or group. It is critical to configure file and folder permissions properly.

In this tutorial, learn how to use the Linux chown command with examples provided.

Linux or UNIX-like system
Access to a terminal/command line
A user with sudo privileges to change the ownership. Remember to run the commands with sudo to execute them properly.

Linux Chown Command Syntax

The basic chown command syntax consists of a few segments. The help file shows the following format:

[OPTIONS] – the command can be used with or without additional options.
[USER] – the username or the numeric user ID of the new owner of a file.
[:] – use the colon when changing a group of a file.
[GROUP] – changing the group ownership of a file is optional.
FILE – the target file.

Superuser permissions are necessary to execute the chown command.

In this guide, we tested the command examples with the chown version 8.28 in Ubuntu 18.04.2 LTS.

To check the chown version on your machine, enter:

The output will look similar to this:

How to Check Ownership of a File in Linux

First, you need to know the original file owner or group before making ownership changes using the chown command.

To check the group or ownership of Linux files and directories in the current location, run the following command:

An example output of the ls command looks like this:

How to Change the Owner of a File

Changing the owner of a file with chown requires you to specify the new owner and the file. The format of the command is:

The following command changes the ownership of a file sample from root to the user test:

Use the same format to change the ownership for both files and directories.

Change the Owner of a File With UID

Instead of a username, you can specify a user ID to change the ownership of a file.

Make sure there is no user with the same name as the numeric UID. If there is, the chown command gives priority to the username, not the UID.

Note: To check a user’s ID, run id -u USERNAME from the terminal.

Change Ownership of Multiple Linux Files

List the target file names after the new user to change the ownership for multiple files. Use single spaces between the file names.

In the following example, root will be the new owner of files sample2 and sample3.

Combine file names and directory names to change their ownership with one command. For example:

Do not forget that the commands are case sensitive.

How to Change the Group of a File

With chown, you can change a group for a file or directory without changing the owning user. The result is the same as using the chgrp command.

Run the chown command using the colon and a group name:

The following example changes the group of the file sample3 from grouptest to group3.

List multiple names of files or directories to make bulk changes.

Change the Group of a File Using GID

Similar to UID, use a group ID (GID) instead of a group name to change the group of a file.

Change Owner and the Group

To assign a new owner of a file and change its group at the same time, run the chown command in this format:

Therefore, to set linuxuser as the new owner and group2 as the new group of the file sample2:

Remember that there are no spaces before or after the colon.

The chown command assigns the owner’s login group to the file when no group is specified.

To do so, define a new user followed by a colon, space, and the target file:

The following example changes the group ownership to the login group of linuxuser:

Transfer Ownership and Group Settings from One File to Another

Rather than changing the ownership to a specific user, you can use the owner and a group of a reference file.

Add the —reference option to the chown command to copy the settings from one file to another:

Remember to type in the names of the files correctly to avoid the error message:

Check Owner and Group Before Making Changes

The chown command —from option lets you verify the current owner and group and then apply changes.

The chown syntax for checking both the user and group looks like this:

The example below shows we first verified the ownership and the group of the file sample3:

Then chown changed the owner to linuxuser and the group to group3.

Check Owner Only

The option —from can be used to validate only the current user of a file.

Check Group Only

Similar to the previous section, you can validate only the group of a file using the option —from .

Here is an example where we verified the current group before changing it:

Remember to use the colon for both group names to avoid error messages.

How to Recursively Change File Ownership

The chown command allows changing the ownership of all files and subdirectories within a specified directory. Add the -R option to the command to do so:

In the following example, we will recursively change the owner and the group for all files and directories in Dir1.

Chown Command and Symbolic Links

To change the owner of a symbolic link, use the -h option. Otherwise, the ownership of the linked file will be changed.

The following image shows how symbolic links behave when -h is omitted.

The owner and group of the symbolic link remain intact. Instead, the owner and the group of the file textfile changed.

To push the changes to the link, run the chown command with the -h flag:

In the following example, we changed the owner and group of a symbolic link.

Display Chown Command Process Details

By default, the terminal does not display the chown process information. To see what happens under the hood, use one of the two command line flags:

The option –v produces the process details even when the ownership stays the same.
The option –c displays the output information only when an owner or group of the target file changes.

For example, if we specify the current owner as a new owner of the file:

The terminal produces the following output:

Switch from -v to -c and there will be no messages in this case. This happens because there are no owner or group changes.

The information is particularly useful with the recursive chown command:

In this example, the output lists all objects affected after running the command.

Suppress Chown Command Errors

To avoid seeing potential error messages when running the chown command, use the -f option:

The example below shows the error message for a non-existent file or directory:

Adding the -f flag suppresses most error messages. However, if you specify an invalid username, the error message appears:

Now you know how to use chown command in Linux to change a file’s user and/or group ownership.

Take extra caution when changing the group or ownership of a file or directories.

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–	Regular file.
b	Block special file.
c	Character special file.
d	Directory.
l	Symbolic link.
p	FIFO.
s	Socket.
w	Whiteout.

Linux show file owner

UNIX / Linux Find File Owner Name

How do I find out owner / group name for a file?

ls -l file mode (permissions)