运行 SQL 时 Bash 中的 `<<-EOSQL` 代码块是什么？
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What is the `<<-EOSQL` code block in Bash when running SQL?
提问by modulitos
I need to execute a bash script containing SQL, so I am using a script to add custom configurations to a Postgres Docker container, according to the docs here:
根据此处的文档，我需要执行一个包含 SQL 的 bash 脚本，因此我使用脚本将自定义配置添加到 Postgres Docker 容器：
https://github.com/docker-library/docs/tree/master/postgres#how-to-extend-this-image
https://github.com/docker-library/docs/tree/master/postgres#how-to-extend-this-image
But I don't know what EOSQLmeans. Here is an example of my script taken from the docs above:
但不知道是什么EOSQL意思。这是我从上面的文档中获取的脚本示例：
#!/bin/bash
set -e
psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" <<-EOSQL
CREATE USER docker;
CREATE DATABASE docker;
GRANT ALL PRIVILEGES ON DATABASE docker TO docker;
CREATE EXTENSION $MY_EXTENSION;
EOSQL
So, what is EOSQL? I cannot seem to find much information about this command or keyword.
那么，什么是 EOSQL？我似乎找不到有关此命令或关键字的太多信息。
回答by Matt
EOSQLis a limit string for a Bash Here Documentblock. The limit string can be any text that doesn't appear in your block. It signifies the start and end of the text block.
EOSQL是Bash Here Document块的限制字符串。限制字符串可以是未出现在您的块中的任何文本。它表示文本块的开始和结束。
Variable substitution will work as normal in a here document:
变量替换将在此处文档中正常工作：
#!/usr/bin/env bash
cat <<-EOF
$MY_EXTENSION
EOF
Then running that with the variable set:
然后使用变量集运行它：
$ MY_EXTENSION=something ./test.sh
something
In Docker you will need ENV MY_EXTENSION=somethingin your Dockerfileor docker run -e MY_EXTENSION=something <image>on your command line for the environment to be setup.
在 Docker 中，您需要ENV MY_EXTENSION=something在命令行中Dockerfile或docker run -e MY_EXTENSION=something <image>命令行中设置环境。
