This script extracts all home directories from /etc/passwd, regardless of their location. It then checks if each home directory contains a Maildir folder. If a Maildir exists, the script displays the total size of the home directory along with the size of the Maildir and its subdirectories.

maildir_report.sh

#!/bin/bash

# Get all home directories from /etc/passwd
HOMEDIRS=$(awk -F: '$6 !~ /^$/ {print $6}' /etc/passwd | sort -u)

# Loop through each home directory
for dir in $HOMEDIRS; do
    MAILDIR="$dir/Maildir"

    # Check if the Maildir exists
    if [ -d "$MAILDIR" ]; then
        echo "=== $dir ==="
        du -h --max-depth=2 "$dir" | grep -E "^|/Maildir"
        echo ""
    fi
done