Module Script Examples

About 1763 wordsAbout 6 min

2026-01-30

This document provides common FolkPatch module script examples that you can copy or modify as needed.

Example 1: Auto Modify Hosts on Boot

Purpose: Automatically replace the system hosts file at boot to block ads or access specific websites.

Script File: `service.sh`

#!/system/bin/sh
# Auto modify hosts file

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/hosts_changer.log

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Hosts Modifier Script Started ==="

# Wait for system to fully boot
sleep 30

# Custom hosts content
CUSTOM_HOSTS="$MODDIR/hosts_custom"

# Check if custom hosts file exists
if [ -f "$CUSTOM_HOSTS" ]; then
    log_msg "Custom hosts file found"
    
    # Backup original hosts (if backup doesn't exist)
    if [ ! -f /system/etc/hosts.bak ]; then
        cp /system/etc/hosts /system/etc/hosts.bak
        log_msg "Original hosts file backed up"
    fi
    
    # Mount custom hosts over system hosts (systemless way)
    mount -o bind "$CUSTOM_HOSTS" /system/etc/hosts
    
    if [ $? -eq 0 ]; then
        log_msg "Hosts file modified successfully"
    else
        log_msg "ERROR: Failed to modify hosts file"
    fi
else
    log_msg "WARNING: Custom hosts file not found"
fi

log_msg "=== Script Execution Completed ==="

Companion File: `hosts_custom`

Create a hosts_custom file in the same module directory:

# Custom hosts file
# Ad blocking example
127.0.0.1 ad.example.com
127.0.0.1 analytics.example.com
0.0.0.0 tracking.example.com

# Other custom entries...

Installation Steps

Create a module package containing:
- module.prop
- service.sh (script above)
- hosts_custom (your hosts content)
Install the module in FolkPatch Manager
Reboot the device

Example 2: Modify System Properties

Purpose: Modify Android system properties, such as displaying a custom ROM name, modifying device model, etc.

Script File: `service.sh`

#!/system/bin/sh
# System property modification example

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/prop_modifier.log

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Property Modifier Script Started ==="

# Wait for system services to start
sleep 10

# Modify ROM display name
resetprop ro.build.display.id "My Awesome ROM v2.0"
log_msg "Modified ro.build.display.id"

# Modify device model (Note: This may affect some apps)
# resetprop ro.product.model "Custom Model"
# log_msg "Modified ro.product.model"

# Modify manufacturer
# resetprop ro.product.manufacturer "Custom Brand"
# log_msg "Modified ro.product.manufacturer"

# Modify Android version display (Display only, does not change actual version)
# resetprop ro.build.version.release "14"
# log_msg "Modified ro.build.version.release"

# Modify security patch date display
# resetprop ro.build.version.security_patch "2099-12-31"
# log_msg "Modified ro.build.version.security_patch"

# Check modified properties
log_msg "Current display version: $(getprop ro.build.display.id)"

log_msg "=== Property Modification Completed ==="

Installation Steps

Create module directory: /data/adb/modules/prop_modifier/
Create module.prop file
Save the script above as service.sh
Set execution permission: chmod +x service.sh
Reboot device

Example 3: Auto Release Memory

Purpose: Periodically clean background processes to release memory (use with caution).

Script File: `service.sh`

#!/system/bin/sh
# Auto memory cleaner service

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/memory_cleaner.log

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Memory Cleaner Service Started ==="

# Run loop in background
(
# Wait for system to fully boot
sleep 120

while true; do
    # Get current memory usage
    MEM_INFO=$(cat /proc/meminfo | grep MemAvailable)
    MEM_AVAILABLE=$(echo $MEM_INFO | awk '{print $2}')
    MEM_TOTAL=$(cat /proc/meminfo | grep MemTotal | awk '{print $2}')
    
    # Calculate available memory percentage
    MEM_PERCENT=$((MEM_AVAILABLE * 100 / MEM_TOTAL))
    
    log_msg "Current available memory: ${MEM_PERCENT}%"
    
    # If available memory is below 15%, perform cleanup
    if [ $MEM_PERCENT -lt 15 ]; then
        log_msg "Low memory, starting cleanup..."
        
        # Drop caches
        echo 3 > /proc/sys/vm/drop_caches
        log_msg "System caches cleaned"
        
        # Check memory after cleanup
        MEM_INFO_AFTER=$(cat /proc/meminfo | grep MemAvailable)
        MEM_AVAILABLE_AFTER=$(echo $MEM_INFO_AFTER | awk '{print $2}')
        MEM_PERCENT_AFTER=$((MEM_AVAILABLE_AFTER * 100 / MEM_TOTAL))
        
        log_msg "Available memory after cleanup: ${MEM_PERCENT_AFTER}%"
    fi
    
    # Check every 10 minutes
    sleep 600
done
) &

log_msg "=== Memory Cleaner Service running in background ==="

Note

This script periodically clears system caches, which may affect app performance
Not recommended for low-memory devices
Adjust cleanup threshold and interval as needed

Example 4: Execute Shell Command at Boot

Purpose: Execute arbitrary commands or scripts automatically at system boot.

Script File: `service.sh`

#!/system/bin/sh
# Execute custom commands at boot

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/startup_commands.log

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Startup Commands Script Started ==="

# Wait for system to fully boot
sleep 20

# Example 1: Create a specific file flag
log_msg "Creating boot flag file"
touch /data/local/tmp/boot_completed.flag

# Example 2: Modify file permissions
log_msg "Modifying specific file permissions"
chmod 644 /data/local/tmp/some_config.txt 2>/dev/null || log_msg "File not found, skipping"

# Example 3: Delete temporary files
log_msg "Cleaning temporary files"
rm -f /data/local/tmp/old_*.tmp 2>/dev/null && log_msg "Temporary files cleaned" || log_msg "No temporary files to clean"

# Example 4: Set CPU frequency (Requires kernel support)
# log_msg "Setting CPU performance mode"
# echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 2>/dev/null || log_msg "Unable to set CPU performance mode"

# Example 5: Start custom service
# if [ -x "$MODDIR/my_service.sh" ]; then
#     log_msg "Starting custom service"
#     nohup sh "$MODDIR/my_service.sh" > /dev/null 2>&1 &
# fi

# Example 6: Log boot info
log_msg "System boot completed, logging info"
echo "Boot time: $(date)" >> $LOGFILE
echo "Device: $(getprop ro.product.model)" >> $LOGFILE
echo "Android version: $(getprop ro.build.version.release)" >> $LOGFILE

log_msg "=== Startup Commands Execution Completed ==="

Example 5: SELinux Policy Patch

Purpose: Add SELinux permissions for specific apps or services.

File 1: `sepolicy.rule`

Create sepolicy.rule file in the module root directory:

# Allow my_app to access specific service
allow my_app system_server_service service_manager find

# Allow shell to execute specific operations (Example)
# allow shell my_custom_file file { read write }

# Allow app to read logs
# allow my_app logd unix_stream_socket connectto

Important

Writing SELinux policies requires professional knowledge
Incorrect rules may lead to security vulnerabilities or system instability
Recommended to refer to default system policies for modification

File 2: `service.sh` (Optional, for verification)

#!/system/bin/sh
# Verify SELinux status

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/selinux_check.log

echo "[$(date)] SELinux Status Check" >> $LOGFILE
echo "Current mode: $(getenforce)" >> $LOGFILE
echo "Policy version: $(cat /sys/fs/selinux/policyvers 2>/dev/null || echo 'N/A')" >> $LOGFILE

Example 6: Conditional Script Execution

Purpose: Decide whether to execute based on device model, Android version, or other conditions.

Script File: `service.sh`

#!/system/bin/sh
# Conditional execution script

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/conditional_script.log

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Conditional Script Started ==="

# Get device info
DEVICE=$(getprop ro.product.device)
MODEL=$(getprop ro.product.model)
ANDROID_VERSION=$(getprop ro.build.version.release)
SDK_VERSION=$(getprop ro.build.version.sdk)

log_msg "Device Info:"
log_msg "  Device: $DEVICE"
log_msg "  Model: $MODEL"
log_msg "  Android: $ANDROID_VERSION (API $SDK_VERSION)"

# Condition 1: Execute only on specific device
if [ "$DEVICE" = "your_device_codename" ]; then
    log_msg "Target device detected, executing specific operations"
    # Add specific device operations here
else
    log_msg "Non-target device, skipping specific operations"
fi

# Condition 2: Execute only on Android 11 and above
if [ "$SDK_VERSION" -ge 30 ]; then
    log_msg "Android 11+ detected, executing advanced features"
    # Add Android 11+ operations here
else
    log_msg "Lower Android version, using compatibility mode"
fi

# Condition 3: Check if specific file exists
if [ -f /system/etc/some_config.xml ]; then
    log_msg "Config file found, executing related operations"
    # Add related operations here
else
    log_msg "Config file not found, skipping"
fi

# Condition 4: Check if specific app is installed
if pm list packages | grep -q "com.example.app"; then
    log_msg "Target app detected, executing app related operations"
    # Add app related operations here
else
    log_msg "Target app not installed"
fi

log_msg "=== Script Execution Completed ==="

Example 7: Module Uninstall Cleanup

Purpose: Execute cleanup operations when the module is uninstalled.

Script File: `uninstall.sh`

#!/system/bin/sh
# Cleanup on module uninstall

LOGFILE=/data/local/tmp/module_uninstall.log

echo "[$(date)] Module uninstall started" >> $LOGFILE

# Clean log files
rm -f /data/local/tmp/module_*.log

# Restore backed up files (if any)
if [ -f /system/etc/hosts.bak ]; then
    echo "[$(date)] Restoring hosts backup" >> $LOGFILE
    # Note: This is just an example, actual operation may require mounting system
    # cp /system/etc/hosts.bak /system/etc/hosts
fi

# Delete created flag files
rm -f /data/local/tmp/boot_completed.flag

echo "[$(date)] Module uninstall completed, cleanup executed" >> $LOGFILE

Hint

uninstall.sh executes automatically when the module is uninstalled, no manual permission setting required.

Example 8: Action Button Script

Purpose: Provide a script that can be manually executed in the manager.

Script File: `action.sh`

#!/system/bin/sh
# Action Button Script - For manual trigger of specific operations

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/action_script.log

echo "[$(date)] Action script execution started" >> $LOGFILE

# Show selection menu (via log output)
echo "Please select operation to execute:"
echo "1. Clean system cache"
echo "2. Restart specific service"
echo "3. Backup current config"

# Example Operation 1: Clean cache
clean_cache() {
    echo "Cleaning system cache..."
    echo 3 > /proc/sys/vm/drop_caches
    echo "Cache cleanup completed"
    echo "[$(date)] System cache cleaned" >> $LOGFILE
}

# Example Operation 2: Restart service (Example, actual service name required)
restart_service() {
    echo "Restarting service..."
    # am restart or other service management command
    echo "Service restart completed"
    echo "[$(date)] Service restarted" >> $LOGFILE
}

# Example Operation 3: Backup config
backup_config() {
    BACKUP_DIR=/sdcard/ModuleBackup
    mkdir -p $BACKUP_DIR
    
    echo "Backing up config..."
    cp -r /data/adb/modules/$MODID $BACKUP_DIR/
    
    echo "Config backed up to: $BACKUP_DIR"
    echo "[$(date)] Config backed up to $BACKUP_DIR" >> $LOGFILE
}

# Execute default operation (Clean cache)
clean_cache

echo "[$(date)] Action script execution completed" >> $LOGFILE

Usage

Enter module details in FolkPatch Manager
Click "Execute Action" button
View execution result and log

Template: General Module Framework

Here is a complete module template containing all common files:

File Structure:

my_module/
├── module.prop
├── customize.sh (Optional)
├── service.sh
├── post-fs-data.sh (Optional)
├── uninstall.sh (Optional)
├── action.sh (Optional)
├── system.prop (Optional)
├── sepolicy.rule (Optional)
└── system/ (Optional, for file mounting)

module.prop:

id=my_custom_module
name=My Custom Module
version=v1.0.0
versionCode=100
author=Your Name
description=This is a custom module for demonstrating module development

service.sh:

#!/system/bin/sh
# General service script template

MODDIR=${0%/*}
LOGFILE=/data/local/tmp/my_module.log

# Log function
log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >> $LOGFILE
}

log_msg "=== Module Service Started ==="
log_msg "Module Path: $MODDIR"

# Wait for system boot
sleep 20

# TODO: Add your script logic here
log_msg "Executing custom operations..."

# Example: Check module status
if [ -f "$MODDIR/disable" ]; then
    log_msg "Module is disabled"
else
    log_msg "Module running normally"
fi

log_msg "=== Module Service Completed ==="

Debugging Tips

Add Detailed Logs in Script

#!/system/bin/sh
MODDIR=${0%/*}
LOGFILE=/data/local/tmp/debug_$(basename $0).log

# Clear old log
> $LOGFILE

log_msg() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] [$(basename $0)] $1" | tee -a $LOGFILE
}

log_msg "Script execution started"
log_msg "Current User ID: $(id)"
log_msg "Current Working Directory: $(pwd)"
log_msg "Module Directory: $MODDIR"
log_msg "Script Path: $0"
log_msg "Environment Variables:"
env >> $LOGFILE

# Your script logic

log_msg "Script execution completed, exit code: $?"

Test Script Syntax

# Check script syntax errors
sh -n /path/to/your/script.sh

# If no output, syntax is correct
# If error exists, line number and error message will be displayed

Precautions

Performance Impact
- Avoid time-consuming operations in post-fs-data.sh (Limit 10 seconds)
- service.sh should use background processes for long-running tasks
Security
- Do not hardcode sensitive info (e.g., passwords, keys)
- Cautiously modify system critical files
- Use resetprop instead of directly modifying /system/build.prop
Compatibility
- Commands and paths may differ across Android versions
- Use conditional checks for device compatibility
- Test on spare device first
Log Management
- Periodically clean log files to avoid using too much space
- Use append mode (>>) instead of overwrite mode (>)

Script Import Guide - Learn how to import scripts
Script Management Guide - Learn how to manage scripts

Copyright

License under:Attribution 4.0 International (CC-BY-4.0)