Linux View Folder Permissions: Quick Commands to Check File Access Rights

Introduction

Understanding and managing file access rights is crucial for maintaining the security and integrity of your Linux system. In Linux, each file and directory has a set of permissions that determine who can read, write, or execute them. To view and manage these permissions, you can use a variety of commands that provide detailed information about file access rights.

In this article, we will explore 40 quick commands that can help you view and check folder permissions in Linux. These commands range from basic ones like ls -l to more advanced ones like getfacl and setfattr. Whether you are a beginner or an experienced Linux user, this article will provide you with a comprehensive guide to understanding and managing file access rights in Linux.

1. ls -l

The ls -l command is one of the most commonly used commands to view file and directory permissions in Linux. When you run this command, it displays a detailed listing of files and directories in the current directory, including their permissions, ownership, size, and modification date.

To use the ls -l command, open a terminal and navigate to the directory you want to inspect. Then, simply type ls -l and press Enter. The output will show the permissions for each file and directory in the following format:

-rw-r–r– 1 user group 4096 Jan 1 00:00 file.txt

In the above example, the file file.txt has the following permissions:

The first character (–) indicates that it is a regular file. If it were a directory, it would be represented by a d.
The next three characters (rw-) represent the permissions for the owner of the file. In this case, the owner has read and write permissions, but not execute permissions.
The next three characters (r–) represent the permissions for the group that the file belongs to. In this case, the group has read-only permissions.
The final three characters (r–) represent the permissions for other users. In this case, other users also have read-only permissions.

By using the ls -l command, you can quickly get an overview of the permissions for all files and directories in a given directory.

2. stat

The stat command provides detailed information about a file or directory, including its permissions. It displays information such as the file type, size, inode number, and access, modification, and change times.

To use the stat command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type stat followed by the name of the file or directory and press Enter. The output will show detailed information about the file or directory, including its permissions.

For example, running stat file.txt might produce the following output:

File: ‘file.txt’
Size: 4096 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 123456 Links: 1
Access: (0644/-rw-r–r–) Uid: ( 1000/ user) Gid: ( 1000/ group)
Access: 2022-01-01 00:00:00.000000000 +0000
Modify: 2022-01-01 00:00:00.000000000 +0000
Change: 2022-01-01 00:00:00.000000000 +0000
Birth: –

In the above example, the permissions for the file file.txt are displayed as 0644, which is equivalent to -rw-r–r–. This means that the owner has read and write permissions, while the group and other users have read-only permissions.

The stat command provides a more detailed view of file permissions, along with other useful information about the file or directory.

3. getfacl

The getfacl command is used to view the Access Control Lists (ACLs) for a file or directory. ACLs provide a more granular level of access control than traditional file permissions, allowing you to specify permissions for specific users or groups.

To use the getfacl command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type getfacl followed by the name of the file or directory and press Enter. The output will show the ACLs for the file or directory.

For example, running getfacl file.txt might produce the following output:

# file: file.txt
# owner: user
# group: group
user::rw-
group::r–
other::r–

In the above example, the ACLs for the file file.txt are displayed. The user::rw- entry indicates that the owner has read and write permissions, while the group::r– and other::r– entries indicate that the group and other users have read-only permissions.

The getfacl command is particularly useful when dealing with complex permission setups that require more fine-grained control over access rights.

4. lsattr

The lsattr command is used to view the attributes of a file or directory, including the immutable attribute. The immutable attribute prevents a file or directory from being modified, renamed, or deleted, even by the root user.

To use the lsattr command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type lsattr followed by the name of the file or directory and press Enter. The output will show the attributes of the file or directory.

For example, running lsattr file.txt might produce the following output:

—-i———– file.txt

In the above example, the i attribute is set for the file file.txt, indicating that it is immutable. This means that the file cannot be modified, renamed, or deleted, even by the root user.

The lsattr command is useful for identifying files or directories with special attributes that may affect their accessibility or modification.

5. find

The find command is a powerful tool for searching for files and directories based on various criteria, including their permissions. It allows you to locate files and directories that match specific permission patterns.

To use the find command, open a terminal and navigate to the directory where you want to start the search. Then, type find followed by the search criteria and press Enter. The output will show a list of files and directories that match the specified criteria.

For example, running find /path/to/directory -perm 644 will search for files in the directory /path/to/directory that have the permissions 644 (equivalent to -rw-r–r–). The output will list all files that match the specified permissions.

The find command is a versatile tool that can be used to search for files and directories based on various permission patterns, allowing you to quickly locate specific files or directories.

6. namei

The namei command is used to resolve the path of a file or directory, displaying the permissions of each component in the path. It provides a detailed view of the permissions for each directory leading to the specified file or directory.

To use the namei command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type namei followed by the name of the file or directory and press Enter. The output will show the permissions for each component in the path.

For example, running namei /path/to/file.txt might produce the following output:

f: /path/to/file.txt
drwxr-xr-x root root /
drwxr-xr-x root root path
drwxr-xr-x user group to
-rw-r–r– user group file.txt

In the above example, the namei command displays the permissions for each component in the path leading to the file file.txt. This allows you to see the permissions for each directory in the path.

The namei command is useful for understanding the permissions of each directory in the path leading to a file or directory, providing a comprehensive view of the access rights.

7. file

The file command is used to determine the type of a file. It can be used to check the permissions of a file or directory and verify if it is a regular file, directory, symbolic link, or other file type.

To use the file command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type file followed by the name of the file or directory and press Enter. The output will show the type of the file or directory.

For example, running file file.txt might produce the following output:

file.txt: ASCII text

In the above example, the file command determines that the file file.txt is an ASCII text file. This information can be useful when checking the permissions of a file or directory.

The file command is a handy tool for quickly determining the type of a file or directory, which can help in understanding its permissions and access rights.

8. du

The du command is used to estimate the disk usage of files and directories. It can also be used to check the permissions of a file or directory and display the disk usage in a human-readable format.

To use the du command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type du followed by the name of the file or directory and press Enter. The output will show the disk usage of the file or directory.

For example, running du -h file.txt might produce the following output:

4.0K file.txt

In the above example, the du command displays the disk usage of the file file.txt as 4.0K (kilobytes). This information can be useful when checking the permissions of a file or directory.

The du command is a useful tool for estimating the disk usage of files and directories, providing insights into their size and potential impact on storage.

9. df

The df command is used to display information about the disk space usage on file systems. It can also be used to check the permissions of a file or directory and provide an overview of the available disk space.

To use the df command, open a terminal and type df followed by the name of the file system or directory you want to inspect. The output will show information about the disk space usage.

For example, running df -h /path/to/directory might produce the following output:

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 100G 50G 50G 50% /

In the above example, the df command displays information about the disk space usage of the file system mounted at /. This information can be useful when checking the permissions of a file or directory.

The df command provides a comprehensive view of the disk space usage on file systems, allowing you to assess the available space and potential limitations.

10. mount

The mount command is used to mount file systems and display information about mounted file systems. It can also be used to check the permissions of a file or directory and provide details about the file system it belongs to.

To use the mount command, open a terminal and type mount followed by the name of the file system or directory you want to inspect. The output will show information about the mounted file systems.

For example, running mount | grep /path/to/directory might produce the following output:

/dev/sda1 on / type ext4 (rw,relatime)

In the above example, the mount command displays information about the file system mounted at /. This information can be useful when checking the permissions of a file or directory.

The mount command provides insights into the file systems that are mounted on your Linux system, allowing you to understand the underlying file system and its permissions.

11. cat

The cat command is used to concatenate and display the contents of files. It can also be used to check the permissions of a file and view its contents.

To use the cat command, open a terminal and navigate to the directory where the file you want to inspect is located. Then, type cat followed by the name of the file and press Enter. The output will display the contents of the file.

For example, running cat file.txt might produce the following output:

This is the content of file.txt.

In the above example, the cat command displays the contents of the file file.txt. This information can be useful when checking the permissions of a file and verifying its contents.

The cat command is a versatile tool for viewing the contents of files, allowing you to inspect the permissions and content of a file simultaneously.

12. chmod

The chmod command is used to change the permissions of files and directories. It allows you to modify the read, write, and execute permissions for the owner, group, and other users.

To use the chmod command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type chmod followed by the desired permissions and the name of the file or directory. The permissions can be specified using either the symbolic or numeric notation.

For example, running chmod u+r file.txt will add read permissions for the owner of the file file.txt. Similarly, running chmod 644 file.txt will set the permissions to -rw-r–r–.

The chmod command is a powerful tool for managing file and directory permissions, allowing you to control who can read, write, and execute them.

13. chown

The chown command is used to change the ownership of files and directories. It allows you to transfer the ownership of a file or directory to a different user or group.

To use the chown command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type chown followed by the desired user or group and the name of the file or directory.

For example, running chown user:group file.txt will change the ownership of the file file.txt to the specified user and group.

The chown command is useful when you need to transfer ownership of a file or directory to a different user or group, allowing you to control who has control over the file or directory.

14. chgrp

The chgrp command is used to change the group ownership of files and directories. It allows you to transfer the group ownership of a file or directory to a different group.

To use the chgrp command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type chgrp followed by the desired group and the name of the file or directory.

For example, running chgrp group file.txt will change the group ownership of the file file.txt to the specified group.

The chgrp command is useful when you need to transfer group ownership of a file or directory to a different group, allowing you to control who has access to the file or directory based on group permissions.

15. id

The id command is used to display the user and group IDs of the current user or a specified user. It provides information about the user and group memberships.

To use the id command, open a terminal and type id followed by the username of the user you want to inspect. If no username is specified, it will display information about the current user.

For example, running id user might produce the following output:

uid=1000(user) gid=1000(group) groups=1000(group),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),116(lpadmin),126(sambashare)

In the above example, the id command displays the user and group IDs for the specified user, as well as the groups the user belongs to.

The id command is useful for checking the user and group IDs, which can be used to set permissions and manage access rights.

16. groups

The groups command is used to display the groups a user belongs to. It provides information about the group memberships of a user.

To use the groups command, open a terminal and type groups followed by the username of the user you want to inspect. If no username is specified, it will display information about the current user.

For example, running groups user might produce the following output:

user : user group adm cdrom sudo dip plugdev lpadmin sambashare

In the above example, the groups command displays the groups the specified user belongs to.

The groups command is useful for checking the group memberships of a user, which can be used to set permissions and manage access rights.

17. whoami

The whoami command is used to display the username of the current user. It provides a quick way to check the username without the need to run other commands.

To use the whoami command, open a terminal and type whoami and press Enter. The output will display the username of the current user.

For example, running whoami might produce the following output:

user

In the above example, the whoami command displays the username of the current user.

The whoami command is a convenient way to quickly check the username, which can be useful when setting permissions or managing access rights.

18. su

The su command is used to switch to another user account. It allows you to temporarily become another user, provided you have the necessary permissions.

To use the su command, open a terminal and type su followed by the username of the user you want to switch to. You will be prompted to enter the password for that user. If successful, you will be logged in as the specified user.

For example, running su user will prompt you to enter the password for the user user. If the password is correct, you will be logged in as the specified user.

The su command is useful when you need to perform administrative tasks or access files and directories that are restricted to certain users.

19. sudo

The sudo command is used to execute commands with the privileges of another user, typically the root user. It allows authorized users to perform administrative tasks without logging in as the root user.

To use the sudo command, open a terminal and type sudo followed by the command you want to execute. You will be prompted to enter your password. If you are authorized to use sudo, the command will be executed with the necessary privileges.

For example, running sudo apt-get update will execute the apt-get update command with root privileges, allowing you to update the system packages.

The sudo command is a powerful tool for performing administrative tasks while maintaining the security and integrity of the system.

20. visudo

The visudo command is used to edit the sudoers file, which controls the privileges granted to users who use the sudo command. It provides a safe and secure way to modify the sudoers file.

To use the visudo command, open a terminal and type visudo and press Enter. This will open the sudoers file in the default text editor specified in your system. Make the necessary changes to the file and save it to apply the modifications.

The visudo command is essential for managing the privileges granted to users who use the sudo command, ensuring that only authorized users have access to administrative tasks.

21. usermod

The usermod command is used to modify user account properties. It allows you to change various attributes of a user account, including the username, user ID, group ID, home directory, and login shell.

To use the usermod command, open a terminal and type usermod followed by the desired options and the username of the user you want to modify. The options can be used to specify the changes you want to make to the user account.

For example, running usermod -l newuser olduser will change the username of the user olduser to newuser.

The usermod command is useful when you need to modify user account properties, such as changing the username or group membership.

22. useradd

The useradd command is used to create a new user account. It allows you to add a new user to the system with the specified username, user ID, group ID, home directory, and login shell.

To use the useradd command, open a terminal and type useradd followed by the desired options and the username of the user you want to create. The options can be used to specify the attributes of the new user account.

For example, running useradd -m -s /bin/bash newuser will create a new user account with the username newuser, a home directory, and the login shell set to /bin/bash.

The useradd command is essential for creating new user accounts on the system, allowing you to manage user access and permissions.

23. userdel

The userdel command is used to delete a user account. It allows you to remove a user from the system, along with their home directory and mail spool.

To use the userdel command, open a terminal and type userdel followed by the username of the user you want to delete. The command will prompt you to confirm the deletion before proceeding.

For example, running userdel -r user will delete the user account user and remove their home directory and mail spool.

The userdel command is useful when you need to remove a user account from the system, ensuring that their access and permissions are revoked.

24. groupmod

The groupmod command is used to modify group properties. It allows you to change various attributes of a group, including the group name and group ID.

To use the groupmod command, open a terminal and type groupmod followed by the desired options and the group name you want to modify. The options can be used to specify the changes you want to make to the group.

For example, running groupmod -n newgroup oldgroup will change the name of the group oldgroup to newgroup.

The groupmod command is useful when you need to modify group properties, such as changing the group name or group ID.

25. groupadd

The groupadd command is used to create a new group. It allows you to add a new group to the system with the specified group name and group ID.

To use the groupadd command, open a terminal and type groupadd followed by the desired options and the group name you want to create. The options can be used to specify the attributes of the new group.

For example, running groupadd newgroup will create a new group with the name newgroup.

The groupadd command is essential for creating new groups on the system, allowing you to manage group access and permissions.

26. groupdel

The groupdel command is used to delete a group. It allows you to remove a group from the system.

To use the groupdel command, open a terminal and type groupdel followed by the group name you want to delete. The command will prompt you to confirm the deletion before proceeding.

For example, running groupdel group will delete the group group from the system.

The groupdel command is useful when you need to remove a group from the system, ensuring that its access and permissions are revoked.

27. passwd

The passwd command is used to change the password of a user account. It allows you to set a new password for a user, provided you have the necessary permissions.

To use the passwd command, open a terminal and type passwd followed by the username of the user you want to change the password for. You will be prompted to enter the new password twice. If successful, the password for the user will be changed.

For example, running passwd user will prompt you to enter the new password for the user user. If the passwords match, the password for the user will be changed.

The passwd command is essential for managing user account passwords, ensuring the security of user accounts and access to the system.

28. chage

The chage command is used to change the password aging information for a user account. It allows you to set various attributes related to password expiration and aging.

To use the chage command, open a terminal and type chage followed by the desired options and the username of the user you want to modify. The options can be used to specify the changes you want to make to the password aging information.

For example, running chage -M 90 user will set the maximum number of days between password changes to 90 for the user user.

The chage command is useful when you need to modify the password aging information for a user account, ensuring that passwords are changed regularly and enforcing password security policies.

29. umask

The umask command is used to set the default file permissions for newly created files and directories. It allows you to specify the permissions that should be masked or removed from the default permissions.

To use the umask command, open a terminal and type umask followed by the desired umask value. The umask value is a three-digit octal number that represents the permissions to be masked or removed.

For example, running umask 022 will set the umask value to 022, which means that write permissions will be removed for group and other users.

The umask command is useful when you want to control the default permissions for newly created files and directories, ensuring that they have the desired access rights.

30. getent

The getent command is used to retrieve entries from various databases, including the user and group databases. It allows you to query information about users and groups, including their names, IDs, and other attributes.

To use the getent command, open a terminal and type getent followed by the desired database and the query. The output will display the entries that match the query.

For example, running getent passwd user will retrieve the entry for the user user from the user database.

The getent command is useful when you need to retrieve information about users and groups, allowing you to manage access rights and permissions.

31. idmapd

The idmapd command is used to manage the ID mapping daemon, which is responsible for mapping user and group IDs between different systems in a network. It allows you to configure and control the ID mapping process.

To use the idmapd command, open a terminal and type idmapd followed by the desired options. The options can be used to specify the configuration settings for the ID mapping daemon.

The idmapd command is useful when you need to manage the ID mapping process in a networked environment, ensuring that user and group IDs are correctly mapped between systems.

32. nfs4_getfacl

The nfs4_getfacl command is used to retrieve the NFSv4 Access Control Lists (ACLs) for a file or directory. It allows you to view the ACLs that are set on NFSv4 file systems.

To use the nfs4_getfacl command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type nfs4_getfacl followed by the name of the file or directory and press Enter. The output will show the NFSv4 ACLs for the file or directory.

The nfs4_getfacl command is particularly useful when dealing with NFSv4 file systems that use ACLs for access control.

33. nfs4_setfacl

The nfs4_setfacl command is used to set the NFSv4 Access Control Lists (ACLs) for a file or directory. It allows you to modify the ACLs that are set on NFSv4 file systems.

To use the nfs4_setfacl command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type nfs4_setfacl followed by the desired ACLs and the name of the file or directory.

The nfs4_setfacl command is useful when you need to modify the ACLs on NFSv4 file systems, allowing you to control access to files and directories in a networked environment.

34. getcap

The getcap command is used to display the capabilities of a file or directory. Capabilities are a way to grant specific privileges to executables, allowing them to perform certain actions without the need for full root privileges.

To use the getcap command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type getcap followed by the name of the file or directory and press Enter. The output will show the capabilities of the file or directory.

The getcap command is particularly useful when dealing with executables that require specific privileges to perform certain actions.

35. setcap

The setcap command is used to set the capabilities of a file or directory. It allows you to grant specific privileges to executables, allowing them to perform certain actions without the need for full root privileges.

To use the setcap command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type setcap followed by the desired capabilities and the name of the file or directory.

The setcap command is useful when you need to grant specific privileges to executables, allowing them to perform certain actions without the need for full root privileges.

36. getent

To use the getent command, open a terminal and type getent followed by the desired database and the query. The output will display the entries that match the query.

The getent command is particularly useful when you need to retrieve information about users and groups, allowing you to manage access rights and permissions.

37. getfacl

The getfacl command is particularly useful when dealing with complex permission setups that require more fine-grained control over access rights.

38. setfacl

The setfacl command is used to set the Access Control Lists (ACLs) for a file or directory. ACLs provide a more granular level of access control than traditional file permissions, allowing you to specify permissions for specific users or groups.

To use the setfacl command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type setfacl followed by the desired ACLs and the name of the file or directory.

The setfacl command is particularly useful when dealing with complex permission setups that require more fine-grained control over access rights.

39. getfattr

The getfattr command is used to view the extended attributes of a file or directory. Extended attributes are additional metadata that can be associated with a file or directory, providing additional information or functionality.

To use the getfattr command, open a terminal and navigate to the directory where the file or directory you want to inspect is located. Then, type getfattr followed by the name of the file or directory and press Enter. The output will show the extended attributes for the file or directory.

The getfattr command is particularly useful when dealing with files or directories that have extended attributes, allowing you to view and manage the additional metadata associated with them.

40. setfattr

The setfattr command is used to set the extended attributes of a file or directory. Extended attributes are additional metadata that can be associated with a file or directory, providing additional information or functionality.

To use the setfattr command, open a terminal and navigate to the directory where the file or directory you want to modify is located. Then, type setfattr followed by the desired extended attributes and the name of the file or directory.

The setfattr command is particularly useful when dealing with files or directories that have extended attributes, allowing you to set and manage the additional metadata associated with them.

Conclusion

Managing file access rights is essential for maintaining the security and integrity of your Linux system. With the 40 quick commands mentioned in this article, you now have a comprehensive toolkit to view and check folder permissions in Linux. From basic commands like ls -l and stat to more advanced ones like getfacl and setfattr, you have the power to understand and manage file access rights with ease.

By using these commands, you can gain insights into the permissions of files and directories, modify permissions as needed, and ensure that access rights are properly configured. Whether you are a beginner or an experienced Linux user, these commands will help you navigate the complexities of file access rights and maintain a secure and well-managed Linux system.

FAQs

Q: How can I check the permissions of a file in Linux?

A: To check the permissions of a file in Linux, you can use the ls -l command. This command displays a detailed listing of files and directories, including their permissions, ownership, size, and modification date.

Q: How can I change the permissions of a file in Linux?

A: To change the permissions of a file in Linux, you can use the chmod command. This command allows you to modify the read, write, and execute permissions for the owner, group, and other users.

Q: How can I view the Access Control Lists (ACLs) of a file in Linux?

A: To view the ACLs of a file in Linux, you can use the getfacl command. This command provides a more granular level of access control than traditional file permissions, allowing you to specify permissions for specific users or groups.