EOF 块中的 Bash EOF 块可能吗？答案

【问题标题】：Bash EOF block in EOF block possible?EOF 块中的 Bash EOF 块可能吗？
【发布时间】：2020-12-15 01:57:55
【问题描述】：

我正在尝试在文件中写入一个包含其自己的 EOF 块的块。这在 bash 中可行吗？

cat > terragrunt.hcl <<'EOF' 
# Automatically generated from script $(basename $0)

# Generate the AWS provider block
generate "provider" {
  path      = "provider.tf"
  if_exists = "overwrite_terragrunt"
  contents  = <<EOF
# Terragrunt root config
provider "aws" {
  # Only these AWS Account IDs may be operated on by this template
  allowed_account_ids = ["${local.account_id}"]
  region = "${local.infra_region}"
  version = "${local.customer_vars.locals.aws_provider_version}"
}
EOF
}

# Automatically generated from script $(basename $0)
EOF

正如预期的那样，它失败了：

❯ ./example.sh 
./example.sh: line 17: syntax error near unexpected token `}'
./example.sh: line 17: `}'

最好的解决办法是什么？

【问题讨论】：

标签： bash eof heredoc

【解决方案1】：

您所说的“EOF 块”实际上称为"Here Document"（通常缩写为“heredoc”），字符串“EOF”实际上可以是您喜欢的任何“单词”。

heredoc 包含匹配分隔符之前的所有内容，因此嵌套两个 heredocs 只是选择两个不同分隔符的情况：

cat > terragrunt.hcl <<'ENDTERRAGRUNT' 
# Automatically generated from script $(basename $0)

# Generate the AWS provider block
generate "provider" {
  path      = "provider.tf"
  if_exists = "overwrite_terragrunt"
  contents  = <<ENDROOTCONFIG
# Terragrunt root config
provider "aws" {
  # Only these AWS Account IDs may be operated on by this template
  allowed_account_ids = ["${local.account_id}"]
  region = "${local.infra_region}"
  version = "${local.customer_vars.locals.aws_provider_version}"
}
ENDROOTCONFIG
}

# Automatically generated from script $(basename $0)
ENDTERRAGRUNT

【讨论】：