function::uid - Linux

Overview

function::uid converts a user-readable string representation of a user’s ID to a user ID and provides any corresponding group information. It performs the inverse function of id.

Syntax

function::uid [USERNAME | UID]

Options/Flags

None.

Examples

To retrieve the user ID and group information for the user "alice":

$ function::uid alice
alice:x:1000:100

To retrieve the user ID for the user with the user ID 1000:

$ function::uid 1000
alice

Common Issues

No Matching User

If the provided user name or ID does not match any existing user, function::uid will return an error message. Make sure to specify a valid user name or ID.

Permission Denied

If the user running the command does not have permission to access the system’s user database, function::uid will return a permission denied error. Check the user’s permissions and ensure they have the necessary privileges.

Integration

function::uid can be used in conjunction with other commands and tools for various tasks:

• Combine with grep to find users matching specific criteria:

function::uid | grep 1000

• Use within scripts to automate user management tasks:

if function::uid $USERNAME > /dev/null; then
  echo "User $USERNAME exists."
else
  echo "User $USERNAME does not exist."
fi

Related Commands

• id: Displays information about the current user’s identity.
• getent / getpwent: Reads information from the system’s user database.
• useradd: Adds a new user to the system.
• userdel: Deletes a user from the system.