1. Check all system users by displaying the contents of /etc/passwd. (Command required in output)
Ravi Vishwakarma2 min read
Understanding the /etc/passwd File
The
/etc/passwdfile stores user account information.Each line represents one user and contains seven fields separated by
:.
Command to View It:
bashCopyEditcat /etc/passwd
Example Entry in /etc/passwd
rubyCopyEditroot:x:0:0:root:/root:/bin/bash
This can be divided into seven parts:
| Field Number | Field Name | Example | Meaning |
| 1️⃣ | Username | root | The login name of the user |
| 2️⃣ | Password Placeholder | x | Indicates the password is stored in /etc/shadow |
| 3️⃣ | User ID (UID) | 0 | Unique ID for the user (0 = root, 1000+ = normal users) |
| 4️⃣ | Group ID (GID) | 0 | The primary group ID for the user |
| 5️⃣ | User Info (Comment Field) | root | A description of the user (often empty or full name) |
| 6️⃣ | Home Directory | /root | The default home folder for the user |
| 7️⃣ | Login Shell | /bin/bash | The default shell for the user |
Example for a Normal User
rubyCopyEditjohn:x:1001:1001:John Doe:/home/john:/bin/bash
| Field | Value | Meaning |
| Username | john | The login name of the user |
| Password Placeholder | x | Password stored in /etc/shadow |
| UID | 1001 | Unique ID (above 1000 = normal user) |
| GID | 1001 | Primary group ID (same as UID by default) |
| Comment | John Doe | Optional user description |
| Home Directory | /home/john | Default folder for storing files |
| Login Shell | /bin/bash | The shell used when logging in |
Special Users in /etc/passwd
root(UID 0): Superuser with full control.daemon,bin,sync(UID < 1000): System accounts for background tasks.nobody(UID 65534): A low-privileged account for security reasons.
Filtering Specific Users
1. List Only Usernames
bashCopyEditcut -d: -f1 /etc/passwd
2. List Only Normal Users (UID ≥ 1000)
bashCopyEditawk -F: '$3 >= 1000 {print $1}' /etc/passwd
3. Check a Specific User
bashCopyEditgrep '^john:' /etc/passwd
Summary
/etc/passwdcontains user details in seven fields.Regular users have UID ≥ 1000, system users have UID < 1000.
Passwords are stored securely in
/etc/shadow.The home directory and default shell define the user’s environment.
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