How to fix E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it? in APT

# Wait 10-15 minutes for automatic updates to complete
# Then try your command again

# Monitor system updates in progress
sudo tail -f /var/log/apt/term.log

# Or check apt update status
sudo lsof /var/lib/apt/lists/lock

# Check what's accessing the lock files
sudo lsof /var/lib/dpkg/lock-frontend
sudo lsof /var/lib/dpkg/lock

# Or search for all apt/dpkg processes
ps aux | grep -E 'apt|dpkg'

# Example output:
# root      1234  0.0  0.1  245920  28512 ?  Ss  10:30  0:00 /usr/bin/apt-get

# The PID (first number) tells you which process is holding the lock

# Check if unattended-upgrades service is running
sudo systemctl status unattended-upgrades

# Stop the service
sudo systemctl stop unattended-upgrades

# Disable automatic upgrades (if not needed)
sudo systemctl disable unattended-upgrades

# Or just kill the process
sudo killall unattended-upgrade

# Give it time to release the lock (10-20 seconds)
sleep 20

# Then try your apt command again
sudo apt update

# Kill all apt-related processes
sudo killall apt apt-get

# Kill dpkg if it's stuck
sudo killall dpkg

# Kill snap daemon if using snaps
sudo killall snapd

# Wait a moment for processes to exit
sleep 5

# Verify processes are gone
ps aux | grep -E 'apt|dpkg'

sudo apt update

# Reconfigure dpkg and clean up incomplete operations
sudo dpkg --configure -a

# This command should output nothing if successful
# If it shows errors, run it again

# Force-clear dpkg locks
sudo dpkg --configure -a

sudo apt update
sudo apt upgrade

# Double-check no apt/dpkg processes are running
ps aux | grep -E 'apt|dpkg'
# Should show only your grep command

# Remove the lock files
sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock
sudo rm /var/lib/dpkg/lock-frontend

# Reconfigure dpkg after removing locks
sudo dpkg --configure -a

# Try apt again
sudo apt update

# Clean up broken packages
sudo apt --fix-broken install

# Or force repair
sudo apt -f install

# Clean package cache
sudo apt clean

# Clean partial packages
sudo apt autoclean

# Force package manager to update
sudo apt update

# Remove partial package files
sudo rm -rf /var/cache/apt/archives/partial/*

# Clear the lock state
sudo rm -rf /var/lib/apt/lists/partial/*

# Force dpkg reconfiguration
sudo dpkg --configure -a

# Update package lists
sudo apt update

# Try upgrade
sudo apt upgrade -y

# Save your work first!
# Then reboot
sudo reboot

# After rebooting, the locks should be cleared
# Try your apt command
sudo apt update

# Check apt can run basic commands
sudo apt update

# List packages without errors
sudo apt list --upgradable

# Try installing a test package (or use your actual package)
sudo apt install -y build-essential

# Verify no lock errors appear

# Check file permissions
ls -la /var/lib/dpkg/lock*
ls -la /var/lib/apt/lists/lock
ls -la /var/cache/apt/archives/lock

# Should show permissions like: -rw-r--r-- or -rw-------
# If not, fix permissions
sudo chmod 644 /var/lib/dpkg/lock*
sudo chmod 644 /var/lib/apt/lists/lock
sudo chmod 644 /var/cache/apt/archives/lock