How to Check System Processes List on Linux Server - Complete Guide

Are you wondering how to list and monitor all system processes on your Linux server? Need to understand what's running, identify resource usage, and detect unauthorized processes automatically? This comprehensive guide shows you multiple methods to check system processes, monitor process activity, detect suspicious processes, and maintain system security on your Linux server.

Why Monitoring System Processes Matters

Monitoring system processes on your Linux server is crucial for security, performance, and troubleshooting. Unauthorized processes can indicate security breaches, malware infections, or compromised accounts. Regular process monitoring helps detect suspicious activity, identify resource-intensive processes, troubleshoot performance issues, and maintain system security compliance.

Method 1: List All Processes with ps Command

The ps command is the most common way to list processes on Linux. It shows running processes with various levels of detail.

Basic Process List

To see all processes:

# List all processes with detailed information
ps aux

# List processes in standard format
ps -ef

# List processes with full command line
ps auxww

Processes in Tree Format

To see process hierarchy:

# Show process tree
pstree

# Show process tree with PIDs
pstree -p

# Show process tree for specific user
pstree -u username

Filter Processes by User

To see processes for specific users:

# Filter processes by user
ps aux | grep username

# Show processes for current user
ps u

# Show processes for root
ps aux | grep root

Method 2: Monitor Process Resource Usage

Understanding which processes consume the most resources helps identify performance bottlenecks.

Sort Processes by Resource Usage

# Sort by memory usage
ps aux --sort=-%mem | head -10

# Sort by CPU usage
ps aux --sort=-%cpu | head -10

# Sort by both memory and CPU
ps aux --sort=-%mem,-%cpu | head -20

Count Total Processes

# Count total processes
ps aux | wc -l

# Count processes by user
ps aux | awk '{print $1}' | sort | uniq -c | sort -rn

Method 3: Automated Process Monitoring with Zuzia.app

Manually checking processes works for occasional audits, but for production servers, you need automated monitoring that alerts you when unexpected processes appear. Zuzia.app provides comprehensive process monitoring through scheduled command execution.

Setting Up Automated Process Monitoring

1. Add Scheduled Task in Zuzia.app Dashboard

   • Navigate to your server in Zuzia.app
   • Click "Add Scheduled Task"
   • Choose "Command Execution" as the task type

2. Configure Process Check Command

   • Enter command: ps aux
   • Set execution frequency: Every 30 minutes to 1 hour
   • Configure alert conditions: Alert when unexpected processes appear
   • Set up filtering for specific process names or users

3. Set Up Notifications

   • Choose notification channels (email, webhook, Slack, etc.)
   • Configure alert thresholds (e.g., alert if new processes detected)
   • Set up escalation rules for suspicious processes

Monitor Specific Processes

For critical processes, create dedicated monitoring tasks:

# Monitor web server processes
ps aux | grep -E "nginx|apache2"

# Monitor database processes
ps aux | grep -E "mysql|postgresql|mariadb"

# Monitor application processes
ps aux | grep "application-name"

Zuzia.app stores all command outputs in its database, allowing you to track process changes over time and identify patterns in process activity.

Method 4: Advanced Process Monitoring Techniques

Track Process Count Over Time

To identify unusual process activity:

# Save current process count
ps aux | wc -l > /tmp/process-count-$(date +%Y%m%d-%H%M%S).txt

# Compare with previous count
diff /tmp/process-count-old.txt /tmp/process-count-new.txt

Detect Unauthorized Processes

To find processes that shouldn't be running:

# Compare with baseline process list
comm -23 <(ps aux | awk '{print $11}' | sort) <(sort /path/to/baseline-processes.txt)

# Find processes with suspicious names
ps aux | grep -iE "backdoor|trojan|malware|suspicious"

Real-World Use Cases for Process Monitoring

Security Audit

For security audits:

# Generate process report
ps aux > process-audit-$(date +%Y%m%d).txt

# Check for root processes
ps aux | grep "^root" > root-processes-$(date +%Y%m%d).txt

# Check for processes with network connections
ps aux | grep -E "LISTEN|ESTABLISHED"

Performance Troubleshooting

When troubleshooting performance:

# Find CPU-intensive processes
ps aux --sort=-%cpu | head -10

# Find memory-intensive processes
ps aux --sort=-%mem | head -10

# Check process resource usage over time
watch -n 5 'ps aux --sort=-%cpu | head -10'

Best Practices for Process Monitoring

1. Monitor Processes Regularly

Check processes every 30 minutes to 1 hour. More frequent checks may be needed for security-sensitive environments. Use Zuzia.app automated monitoring to check processes continuously without manual intervention.

2. Maintain Baseline Process Lists

Keep baseline process lists for comparison. Update baselines after authorized installations to reduce false positives.

3. Monitor Process Counts

Track total process counts over time. Sudden increases might indicate issues or attacks.

4. Focus on Resource-Intensive Processes

Regularly review top CPU and memory-consuming processes to identify applications that might need optimization.

5. Set Up Alerts for Suspicious Processes

Configure alerts for processes with suspicious names, unexpected users, or unusual resource usage patterns.

Troubleshooting Common Process Issues

Too Many Processes

If there are too many processes:

# Identify processes consuming resources
ps aux --sort=-%mem | head -20

# Check for zombie processes
ps aux | grep -E "Z|defunct"

# Find processes that should be stopped
ps aux | grep -E "stopped|killed"

Process Not Showing

If a process isn't showing:

# Check if process is running
pgrep process-name

# Check process status
ps aux | grep process-name

# Check system logs
dmesg | grep process-name

FAQ: Common Questions About Checking Processes

How often should I check processes?

We recommend checking processes every 30 minutes to 1 hour. More frequent checks may be needed for security-sensitive environments. Use Zuzia.app automated monitoring to check processes continuously without manual intervention.

What if unexpected processes are detected?

You'll receive notifications when unexpected processes are detected through Zuzia.app. You can then verify whether processes are authorized or indicate a security concern. Check process details, verify with system administrators, and take appropriate security actions if unauthorized processes are confirmed.

Can I filter processes by resource usage?

Yes, you can combine ps aux with sorting and filtering. For example: ps aux --sort=-%mem | head -10 shows top memory-consuming processes, or ps aux --sort=-%cpu | head -10 shows top CPU-consuming processes.

How do I detect unauthorized processes?

Set up automated monitoring in Zuzia.app that compares current process lists with baseline lists. Any processes in the current list that aren't in the baseline indicate new processes that should be investigated. Also monitor for processes with suspicious names or unusual resource usage.

Can I track process changes over time?

Yes, use Zuzia.app to store process lists in its database. This allows you to track process changes over time, identify trends, and detect anomalies. Compare current processes with historical patterns to identify unusual activity.

How can I monitor processes across multiple servers?

Zuzia.app allows you to add multiple servers and monitor processes across all of them simultaneously. Each server executes commands independently, and all results are stored in Zuzia.app's database for centralized monitoring and analysis.

Does Zuzia.app use AI to analyze process patterns?

Yes, if you have Zuzia.app's full package, AI analysis is enabled. The AI can detect patterns in process activity, identify suspicious processes, predict potential security threats, and suggest security improvements based on historical process data and machine learning algorithms.