find - Search Files in Linux

# Find by name
find /path -name "filename.txt"
find . -name "*.js"

# Find by type
find . -type f         # Files only
find . -type d         # Directories only

# Find by size
find . -size +100M     # Larger than 100MB
find . -size -1M       # Smaller than 1MB

# Find and execute
find . -name "*.log" -delete
find . -type f -exec chmod 644 {} \;