When attempting to delete a directory in Linux using rm -rf, you might encounter the frustrating "Device or resource busy" error. This commonly occurs with system directories like /var/www/html that are actively being used by services or mounted devices.

Here are typical situations where you'll see this error:

• The directory is currently mounted (NFS, bind mounts, etc.)
• A process has files open within the directory
• The directory is being used as a working directory by some process
• It's part of an active chroot environment

First, identify what's using the directory:

# Find mounted filesystems
mount | grep /var/www/html

# Find processes using the directory
lsof +D /var/www/html

# Alternative process check
fuser -vm /var/www/html

Case 1: Directory is Mounted

If it's a mount point, you'll need to unmount first:

umount /var/www/html
rm -rf /var/www/html

Case 2: Processes Using the Directory

For processes locking the directory, either stop them or kill them:

# Graceful stop (Apache example)
sudo systemctl stop apache2

# Force kill all processes using the directory
fuser -km /var/www/html

Case 3: Working Directory Conflict

If a shell or process has it as current directory:

# Find the processes
lsof +D /var/www/html | grep cwd

# Then either:
cd /tmp  # if it's your shell
# OR
kill -9 PID  # for other processes

For stubborn cases, you can use mount namespaces:

unshare -m
umount -l /var/www/html
exit
rm -rf /var/www/html

• Always check directory usage before deletion
• Consider using rmdir for mount points
• Implement proper service stopping procedures in scripts
• Use strace to debug when other methods fail

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When attempting to remove a directory like /var/www/html with standard rm -rf commands, Linux systems may return the frustrating "Device or resource busy" error. This typically occurs when:

• The directory is mounted as a filesystem
• Processes have open file handles within the directory
• The directory acts as a working directory for active processes

Before attempting deletion, identify what's locking the directory:

# Find processes using the directory
lsof +D /var/www/html

# Check mount points
mount | grep "/var/www/html"

# Alternative lsof syntax
fuser -vm /var/www/html

Method 1: Unmount First

If the directory is mounted:

umount -l /var/www/html
rm -rf /var/www/html

Method 2: Kill Attached Processes

When processes are using files:

# Kill all processes using the directory
fuser -km /var/www/html

# Then remove
rm -rf /var/www/html

Method 3: The Nuclear Option

For stubborn cases where standard methods fail:

# Reboot into single-user mode
init 1

# Then attempt removal
rm -rf /var/www/html

# Return to normal runlevel
init 5

• Always check directory usage before deletion
• Consider using lsof or fuser in scripts
• For web directories, stop Apache/Nginx first

When dealing with NFS or complex mounts:

umount -f -l /mnt/problem_directory
rmdir /mnt/problem_directory