Command documentation sourced from the linux-command project This comprehensive command reference is part of the linux-command documentation project.

chfn - Change User Finger Information

The chfn command is a system administration utility that allows users to change their finger information stored in the /etc/passwd file. This information includes the user's real name, office location, office phone number, and home phone number. The finger information is used by various system utilities and displayed when users query information about other accounts using the finger command. It's part of the shadow-utils package and provides controlled access to modify user account GECOS (General Electric Comprehensive Operating System) field information.

Basic Syntax

chfn [OPTIONS] [USERNAME]
chfn [-f FULL_NAME] [-o OFFICE] [-p OFFICE_PHONE] [-h HOME_PHONE] [USERNAME]

Information Fields

The chfn command manages five information fields in the user's GECOS field:

Full Name (-f) - User's real name or display name
Room/Office (-o) - Office location or room number
Office Phone (-p) - Office telephone number
Home Phone (-h) - Home telephone number
Other - Additional information (accessed interactively)

Common Options

Field Specification Options

-f, --full-name FULL_NAME - Set user's full name
-o, --office OFFICE - Set office room number or location
-p, --office-phone OFFICE_PHONE - Set office phone number
-h, --home-phone HOME_PHONE - Set home phone number
-r, --room ROOM - Alternative option for office room number

Control Options

-R, --root CHROOT_DIR - Directory to chroot into
-s, --shell SHELL - Change user login shell (some implementations)
-u, --help - Display help message
-v, --version - Display version information

Interactive Options

-i, --interactive - Force interactive mode
-q, --quiet - Suppress informational messages

Usage Examples

Basic User Information Management

Interactive Information Update

# Change your own finger information interactively
chfn

# Change another user's information (requires root privileges)
sudo chfn username

# Change specific user's information with prompts
sudo chfn -i john

Setting Specific Fields

# Set full name only
chfn -f "John Smith"

# Set office location
chfn -o "Room 301, Building A"

# Set office phone
chfn -p "555-1234"

# Set home phone
chfn -h "555-5678"

# Set multiple fields at once
chfn -f "Jane Doe" -o "Office 204" -p "555-9876" -h "555-5432"

Modifying Other User Information

# Set full name for another user (requires root)
sudo chfn -f "Robert Johnson" robert

# Set office information for user
sudo chfn -o "Engineering Department" -p "555-1000" alice

# Complete information update for user
sudo chfn -f "Mary Wilson" -o "Room 502" -p "555-2345" -h "555-6789" mary

System Administration

Bulk User Information Updates

# Script to update department information
#!/bin/bash
# Update office information for multiple users

for user in alice bob charlie; do
    sudo chfn -o "IT Department" "$user"
    echo "Updated office for $user"
done

# Set full names from a file
while IFS=',' read -r username fullname; do
    sudo chfn -f "$fullname" "$username"
done < user_names.csv

User Account Migration

# Migrate user information with formatting
sudo chfn -f "John A. Smith (Contractor)" john

# Add department information
sudo chfn -o "Sales Department - West Wing" sales_user

# Set contact information for new employees
sudo chfn -f "New Employee" -o "Temp Office" -p "Extension 123" newhire

Advanced Information Management

Complex Field Formatting

# Include title and department in name
chfn -f "Dr. Sarah Chen, PhD"

# Add location details
chfn -o "Building 2, Floor 3, Room 305"

# Include country codes in phone numbers
chfn -p "+1-555-123-4567" -h "+1-555-987-6543"

# Combine information with separators
chfn -f "Mark Davis | Project Manager" -o "HQ Office | Executive Floor"

Temporary Information Updates

# Set temporary contact information
sudo chfn -o "Remote Worker" -h "555-TEMP" remote_user

# Update for project duration
chfn -o "Project Team Room" -p "Project Extension: 4567"

# Add role information
sudo chfn -f "Alice Brown (System Administrator)" alice

Practical Examples

Corporate Environment Setup

New Employee Onboarding

#!/bin/bash
# Script for setting up new employee information

USERNAME=$1
FULLNAME=$2
DEPARTMENT=$3
EXTENSION=$4

if [ -z "$USERNAME" ] || [ -z "$FULLNAME" ]; then
    echo "Usage: $0 <username> <full_name> [department] [extension]"
    exit 1
fi

# Set comprehensive user information
sudo chfn -f "$FULLNAME" "$USERNAME"

if [ -n "$DEPARTMENT" ]; then
    sudo chfn -o "$DEPARTMENT" "$USERNAME"
fi

if [ -n "$EXTENSION" ]; then
    sudo chfn -p "Ext: $EXTENSION" "$USERNAME"
fi

echo "Updated finger information for $USERNAME"

Department Organization

# IT Department users
sudo chfn -f "Alice Johnson (Senior Admin)" -o "IT Department | Server Room" alice
sudo chfn -f "Bob Smith (Network Engineer)" -o "IT Department | Network Ops" bob
sudo chfn -f "Carol Davis (Security Analyst)" -o "IT Department | Security Office" carol

# Sales Department users
sudo chfn -f "David Wilson (Sales Manager)" -o "Sales Department | Executive Suite" david
sudo chfn -f "Eve Brown (Account Executive)" -o "Sales Department | Regional Office" eve

Educational Institution

Faculty Information Setup

# Professor information
sudo chfn -f "Dr. Michael Roberts, PhD" -o "Physics Department | Room 204" michael
sudo chfn -p "555-1010" -h "555-1011" michael

# Teaching assistant
sudo chfn -f "Jennifer Lee (TA)" -o "Physics Department | Lab 301" jennifer
sudo chfn -p "555-1020" jennifer

Student Account Management

# Update student information batch
#!/bin/bash
# Student information update script

while IFS=',' read -r student_id full_name dorm room; do
    username="student_$student_id"
    if id "$username" &>/dev/null; then
        sudo chfn -f "$full_name" -o "$dorm - Room $room" "$username"
        echo "Updated: $username"
    else
        echo "User not found: $username"
    fi
done < student_list.csv

Remote Work Setup

Teleworker Configuration

# Remote user setup
sudo chfn -f "John Miller (Remote)" -o "Remote Worker - Home Office" john
sudo chfn -p "Teams: @johnmiller" -h "Mobile: 555-CELL" john

# Hybrid worker
sudo chfn -f "Sarah Davis (Hybrid)" -o "Main Office Mon/Wed/Fri" sarah
sudo chfn -p "Office: 555-2000" -h "Home: 555-3000" sarah

Integration and Automation

Shell Script Integration

User Provisioning Script

#!/bin/bash
# Complete user provisioning with finger information

create_user_with_info() {
    local username=$1
    local fullname=$2
    local department=$3
    local office=$4
    local phone=$5

    # Create user account
    sudo useradd -m -s /bin/bash "$username"

    # Set initial password
    echo "$username:TempPass123!" | sudo chpasswd

    # Set finger information
    sudo chfn -f "$fullname" "$username"
    [ -n "$department" ] && sudo chfn -o "$department" "$username"
    [ -n "$office" ] && sudo chfn -o "$office" "$username"
    [ -n "$phone" ] && sudo chfn -p "$phone" "$username"

    echo "Created user: $username with finger information"
}

# Usage example
create_user_with_info "jdoe" "John Doe" "Engineering" "Room 301" "555-1234"

Information Validation Script

#!/bin/bash
# Validate and fix user finger information

validate_user_info() {
    local username=$1

    # Get current finger information
    finger_output=$(finger "$username" 2>/dev/null | grep "Name:")

    if [ -z "$finger_output" ]; then
        echo "Warning: No finger information for $username"
        return 1
    fi

    echo "Current info for $username: $finger_output"
}

# Fix missing information
fix_user_info() {
    local username=$1
    local default_name=$2

    current_name=$(getent passwd "$username" | cut -d: -f5 | cut -d, -f1)

    if [ -z "$current_name" ] || [ "$current_name" = "$username" ]; then
        sudo chfn -f "$default_name" "$username"
        echo "Updated full name for $username to: $default_name"
    fi
}

# Process all users
for user in $(awk -F: '$3 >= 1000 && $3 < 60000 {print $1}' /etc/passwd); do
    validate_user_info "$user"
done

System Integration

LDAP/Active Directory Integration

#!/bin/bash
# Sync finger information with LDAP

sync_ldap_finger_info() {
    local username=$1
    local ldap_fullname=$2
    local ldap_office=$3
    local ldap_phone=$4

    # Update local finger info from LDAP
    sudo chfn -f "$ldap_fullname" "$username"
    [ -n "$ldap_office" ] && sudo chfn -o "$ldap_office" "$username"
    [ -n "$ldap_phone" ] && sudo chfn -p "$ldap_phone" "$username"

    echo "Synced LDAP info for $username"
}

# Batch sync from LDAP query
ldapsearch -x -LLL "(objectClass=person)" cn telephoneNumber physicalDeliveryOfficeName | \
while read -r line; do
    case $line in
        dn:*) username=$(echo "$line" | sed 's/.*uid=\([^,]*\).*/\1/');;
        cn:*) fullname=${line#cn: };;
        telephoneNumber:*) phone=${line#telephoneNumber: };;
        physicalDeliveryOfficeName:*) office=${line#physicalDeliveryOfficeName: };;
        "")
            if [ -n "$username" ]; then
                sync_ldap_finger_info "$username" "$fullname" "$office" "$phone"
            fi
            username=""
            ;;
    esac
done

Advanced Usage

Information Security

Sensitive Information Handling

# Set generic information for security-sensitive accounts
sudo chfn -f "Service Account" -o "System Service" service_user
sudo chfn -f "Database Account" -o "Database Server" db_user

# Remove personal information for privileged accounts
sudo chfn -f "System Administrator" -o "IT Department" admin
sudo chfn -p "" -h "" admin

# Set contact information for escalation
sudo chfn -f "On-Call Administrator" -o "24/7 Support" -p "555-HELP" oncall

Compliance and Auditing

#!/bin/bash
# Audit user finger information for compliance

audit_user_info() {
    echo "=== User Finger Information Audit ==="
    echo "Date: $(date)"
    echo ""

    while IFS=: read -r username _ _ _ _ rest; do
        # Skip system users
        if [ "$username" = "root" ] || [ "${username#*nobody}" != "$username" ]; then
            continue
        fi

        finger_info=$(getent passwd "$username" | cut -d: -f5)
        echo "User: $username"
        echo "Info: $finger_info"
        echo ""
    done < /etc/passwd
}

# Check for missing or incomplete information
check_completeness() {
    echo "=== Checking Information Completeness ==="

    while IFS=: read -r username _ _ _ _ gecos; do
        # Skip system accounts
        uid=$(id -u "$username" 2>/dev/null)
        if [ "$uid" -lt 1000 ] || [ -z "$uid" ]; then
            continue
        fi

        if [ -z "$gecos" ] || [ "$gecos" = "," ]; then
            echo "WARNING: No finger information for $username"
        elif [[ ! "$gecos" =~ [a-zA-Z] ]]; then
            echo "WARNING: Invalid finger information for $username: $gecos"
        fi
    done < /etc/passwd
}

audit_user_info
check_completeness

Multi-Environment Management

Development vs Production

# Development environment
sudo chfn -f "Alice Developer (Dev Env)" -o "Development Team" alice
sudo chfn -f "Bob Tester (QA)" -o "Quality Assurance" bob

# Production environment
sudo chfn -f "Alice Developer (Prod)" -o "Production Support" alice
sudo chfn -f "Bob Administrator (Prod)" -o "Production Operations" bob

# Staging environment
sudo chfn -f "Alice Developer (Staging)" -o "Staging Environment" alice

Troubleshooting

Common Issues

Permission Problems

# Permission denied error
# Solution: Use sudo or ensure you're changing your own information
sudo chfn -f "New Name" username

# User not found error
# Solution: Verify user exists
id username
getent passwd username

# Password database busy error
# Solution: Wait for other user management operations to complete
sudo chfn -f "Name" username

Information Display Issues

# Finger command not showing updated information
# Solution: Check if finger daemon is running
systemctl status finger

# Clear finger cache if exists
sudo systemctl restart finger

# Verify information in passwd file
getent passwd username | cut -d: -f5

Field Limitations

# Information too long for field
# Solution: Use abbreviations or shorten information
chfn -f "John S." -o "B2-R301" -p "x1234"

# Special characters causing issues
# Solution: Escape special characters or use quotes
chfn -f "John O'Connor" -o "Room \#101" -p "555-1234"

Recovery and Repair

Corrupted Finger Information

#!/bin/bash
# Repair corrupted finger information

repair_user_info() {
    local username=$1
    local backup_file="/etc/passwd.backup"

    # Create backup before making changes
    sudo cp /etc/passwd "$backup_file"

    # Reset to basic information
    sudo chfn -f "$username" "$username"
    sudo chfn -o "" -p "" -h "" "$username"

    echo "Reset finger information for $username"
    echo "Backup saved to $backup_file"
}

# Batch repair for all users
for user in $(awk -F: '$3 >= 1000 {print $1}' /etc/passwd); do
    if [[ $(getent passwd "$user" | cut -d: -f5) =~ [^a-zA-Z0-9,\.\- ] ]]; then
        repair_user_info "$user"
    fi
done

finger - Display user information
passwd - Change user password
chsh - Change user shell
chage - Change user password expiry
useradd - Create new user account
usermod - Modify user account
getent - Get entries from administrative database
whoami - Display effective username
id - Display user and group information

Best Practices

Use real names - Keep finger information professional and accurate
Limit sensitive data - Avoid including passwords or confidential information
Maintain consistency - Use standard formats across the organization
Regular updates - Keep information current when users change roles or locations
Security awareness - Don't include personal contact information for service accounts
Department organization - Use consistent department naming conventions
Phone formatting - Use standard phone number formats for easy parsing
Audit regularly - Periodically review user finger information for accuracy

Performance Tips

Batch operations - Update multiple users efficiently with scripts
Field limits - Keep information within standard field length limits
System load - Avoid mass updates during peak system usage times
Database locking - Be aware of passwd file locking during updates
Backup strategies - Maintain backups of user information before bulk changes
Testing environments - Test scripts in non-production environments first
Logging changes - Maintain audit trails for information changes

The chfn command is an essential system administration tool for maintaining accurate user information across Unix/Linux systems. Its ability to manage contact and organizational details makes it valuable for both small organizations and large enterprise environments where proper user identification and contact information is crucial for effective system administration and user support.

This documentation provides comprehensive coverage of the chfn command, from basic usage to advanced system administration scenarios.

Basic Syntax​

Information Fields​

Common Options​

Field Specification Options​

Control Options​

Interactive Options​

Usage Examples​

Basic User Information Management​

Interactive Information Update​

Setting Specific Fields​

Modifying Other User Information​

System Administration​

Bulk User Information Updates​

User Account Migration​

Advanced Information Management​

Complex Field Formatting​

Temporary Information Updates​

Practical Examples​

Corporate Environment Setup​

New Employee Onboarding​

Department Organization​

Educational Institution​

Faculty Information Setup​

Student Account Management​

Remote Work Setup​

Teleworker Configuration​

Integration and Automation​

Shell Script Integration​

User Provisioning Script​

Information Validation Script​

System Integration​

LDAP/Active Directory Integration​

Advanced Usage​

Information Security​

Sensitive Information Handling​

Compliance and Auditing​

Multi-Environment Management​

Development vs Production​

Troubleshooting​

Common Issues​

Permission Problems​

Information Display Issues​

Field Limitations​

Recovery and Repair​

Corrupted Finger Information​

Related Commands​

Best Practices​

Performance Tips​