cat > hello.py << EOF
#!/usr/bin/env python
from __future__ import print_function
import sys
print("#stdout", file=sys.stdout)
print("#stderr", file=sys.stderr)
for line in sys.stdin:
    print(line, file=sys.stdout)
EOF
# Variables will be expanded if the first "EOF" is not quoted

cat <<EOF
This is line 1.
This is line 2.
This is line 3.
EOF

## Variable Expansion:
name="Alice"
cat <<EOF
Hello, $name!
EOF

## Suppressing Variable Expansion:
name="Alice"
cat <<'EOF'
Hello, $name!
EOF