How to fix Error: Invalid multi-line string in Terraform

The Terraform error message will show you the exact line number where the parse error occurred. Look at that line and the lines around it in your .tf file to find the problematic string.

# INCORRECT - String split across lines:
local_file = "/path/to/file/that/
contains/multiple/paths"

# This will trigger: Error: Invalid multi-line string

Use your editor's line numbering or the error message line reference to quickly locate the issue. The problematic string will be the one using quotes that extends beyond a single line.

Terraform offers three ways to handle content that spans multiple lines. Choose the one that fits your use case:

Option 1: Use heredoc syntax (recommended for true multi-line strings)

user_data = <<EOF
#!/bin/bash
echo 'Hello World'
echo 'Installing packages'
apt-get update
EOF

Heredoc syntax uses <<IDENTIFIER to start and must have the identifier on its own line to end. Content between is literal (no quote escaping needed).

Option 2: Use indented heredoc for cleaner formatting

script_content = <<-EOT
  #!/bin/bash
  echo 'This is indented'
  echo 'Terraform will dedent it automatically'
EOT

The <<- variant allows you to indent the closing marker and content, making code more readable.

Option 3: Use escape sequences for simple line breaks

message = "Line 1\nLine 2\nLine 3"
description = "This is a long string that needs a break\nwith explicit newline characters"

Use \n for newlines, \t for tabs, and \\ for literal backslashes within a single-line quoted string.

Take your problematic multi-line string and rewrite it using one of the three approaches above.

Example conversion:

Before (incorrect):

resource "aws_instance" "example" {
  user_data = "#!/bin/bash
edit configuration file
install software"
}

After (correct - using heredoc):

resource "aws_instance" "example" {
  user_data = <<EOF
#!/bin/bash
edit configuration file
install software
EOF
}

Or after (correct - using escape sequences):

resource "aws_instance" "example" {
  user_data = "#!/bin/bash\nedit configuration file\ninstall software"
}

Choose heredoc for readability when dealing with scripts or large blocks of text. Use escape sequences for shorter strings where inline text is acceptable.

When using heredoc, be aware of how special characters are handled:

In quoted strings (with escape sequences):
- \n → newline
- \t → tab
- \" → literal quote
- \\ → literal backslash
- ${...} → interpolation (use \${...} to escape)
- %{...} → directives (use %{~ ...} to strip whitespace)

In heredoc strings:

config = <<EOC
No escape sequences needed here
Backslashes are literal: C:\\Users\\Data
But interpolation still works: ${var.name}
End marker EOC must be at line start
EOC

Heredoc preserves literal backslashes and spaces, making them ideal for configuration files, scripts, and data that shouldn't be escaped. Use <<- if you want to indent the closing marker.

After fixing the string syntax, validate that your configuration is now correct:

# Validate the syntax
terraform validate

# Check for other issues and format
terraform fmt -recursive

# Generate a plan to ensure resources are understood correctly
terraform plan

The terraform validate command will parse all your .tf files and report any remaining syntax errors. If you see 'Success! The configuration is valid', the multi-line string error is resolved. If you still get parsing errors, review the error line number and apply the same fix to any other problematic strings.