killall

Overview

The killall command kills processes by name. It sends a signal to all processes running any of the specified commands.

Syntax

killall [options] name...

Common Options

Option Description
-e Require exact match
-I Case insensitive
-i Interactive
-l List signals
-q Quiet mode
-r Use regex
-s signal Send signal
-u user Kill user’s processes
-v Verbose mode
-w Wait for processes to die
-y Younger than time
-o Older than time

Key Use Cases

  1. Process cleanup
  2. Application restart
  3. User process termination
  4. System maintenance
  5. Batch process control

Examples with Explanations

Example 1: Basic Usage

killall firefox

Kill all Firefox processes

Example 2: Specific Signal

killall -9 httpd

Force kill all Apache processes

Example 3: Interactive Mode

killall -i process_name

Prompt before killing each process

Understanding Output

  • No output on success
  • With -v:
    • Killed process information
  • Error messages for:
    • No process found
    • Permission denied
    • Invalid signal
    • Pattern errors

Common Usage Patterns

  1. Kill by age:

    killall -o 15m process_name

  2. Kill user processes:

    killall -u username process_name

  3. Wait for completion:

    killall -w process_name

Performance Analysis

  • Process name lookup
  • Pattern matching overhead
  • Signal delivery time
  • Multiple process handling
  • System resource impact

Additional Resources

Best Practices

  1. Use exact matching
  2. Verify process names
  3. Interactive mode for safety
  4. Check user permissions
  5. Document actions

Safety Considerations

  1. Avoid system processes
  2. Use interactive mode
  3. Verify process names
  4. Check dependencies
  5. Backup important data