Learn more about how to view Linux user UID and GID

User UID and GID are numerical identifiers used to identify users and groups in Linux systems. When using a Linux system, we often need to view the user's UID and GID in order to manage user and file permissions. This article will provide an in-depth introduction to the various ways to view user UID and GID in Linux systems, and attach specific code examples.

1. View the user UID and GID through commands

1. View the UID and GID of the current user:

   id

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After running the above command, the system will display the UID, GID and associated group information of the current user.

2. View the UID and GID of the specified user:

   id <username>

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Run the above command to The UID, GID and associated group information of the user with the specified username will be displayed.

3. View the UID and GID of all users:

   cat /etc/passwd | cut -d: -f1,3

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Run the above command, the system will list the username and UID information of all users.

4. View the GID of the group to which the user belongs:

   id -g -n <username>

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The above command You can view the GID of the primary group to which a specified user belongs.

5. List the GIDs of all groups in the system:

   cat /etc/group | cut -d: -f1,3

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After running the above command, the system will list the group names of all groups and their corresponding GIDs.

2. View user UID and GID through system files

1. The main system files for viewing user UID and GID include:
2. /etc/passwd: Contains user list and its corresponding UID and GID information;
3. /etc/group: Contains the group list and its corresponding GID information.

By viewing these two system files, you can obtain detailed information about users and groups.

2. View the contents of the above system files through the command:

   cat /etc/passwd
   cat /etc/group

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#Through the above command, you can view the user and group information in the system file.

3. Obtain user UID and GID through programming language

1. Python code example:

   import os
   import pwd
   import grp
   
   def get_uid_gid(username):
    try:
        uid = pwd.getpwnam(username).pw_uid
        gid = pwd.getpwnam(username).pw_gid
        print(f"The UID of user {username} is: {uid}")
        print(f"The GID of the group to which user {username} belongs is: {gid}")
    exceptKeyError:
        print(f"User {username} not found")
   
   if __name__ == "__main__":
    username = "user1"
    get_uid_gid(username)

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The above Python code example obtains the UID and GID information of the user with the specified username through the pwd module.

4. Summary

This article introduces various ways to view user UID and GID in Linux systems, including using commands, viewing system files, and obtaining user UID and GID information through programming languages. It is very important for system administrators and developers to have a deep understanding of how to view user UIDs and GIDs to help them better manage user and file permissions. I hope the content of this article will be helpful to readers.

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