29.13 User Database

This section describes how to search and scan the database of registered users. The database itself is kept in the file /etc/passwd on most systems, but on some systems a special network server gives access to it.

• User Data Structure: What each user record contains.
• Lookup User: How to look for a particular user.
• Scanning All Users: Scanning the list of all users, one by one.
• Writing a User Entry: How a program can rewrite a user's record.