我启动EC2实例，通过调用ec2-run-instances从简单的bash脚本，并希望在该实例上进行进一步的操作（如准弹性IP），为此，我需要的实例ID。

I'm launching an EC2 instance, by invoking ec2-run-instances from simple a bash script, and want to perform further operations on that instance (e.g. associate elastic IP), for which I need the instance id.

该命令是一样的东西 EC2-运行情况AMI-dd8ea5a9 -K pk.pem -C cert.pem --region欧盟 - 西-1 -t -n c1.medium 1 ，它的输出：

The command is something like ec2-run-instances ami-dd8ea5a9 -K pk.pem -C cert.pem --region eu-west-1 -t c1.medium -n 1, and its output:

RESERVATION r-b6ea58c1    696664755663    default
INSTANCE    i-945af9e3    ami-dd8ea5b9    pending    0    c1.medium    2010-04-15T10:47:56+0000    eu-west-1a    aki-b02a01c4    ari-39c2e94d   

在这个例子中， I-945af9e3 的ID，我后。

In this example, i-945af9e3 is the id I'm after.

所以，我需要一个简单的方法来分析，从该命令返回的ID - 你将如何去这样做呢？我AWK是有点生疏......随意使用任何工具可以在一个典型的Linux机器。 （如果有一种方式来获得它直接使用EC2-API的工具，那就更好了。但AFAIK没有EC2命令，例如返回最近推出的实例的ID。）

So, I'd need a simple way to parse the id from what the command returns - how would you go about doing it? My AWK is a little rusty... Feel free to use any tool available on a typical Linux box. (If there's a way to get it directly using EC2-API-tools, all the better. But afaik there's no EC2 command to e.g. return the id of the most recently launched instance.)

推荐答案

好吧，至少这样的事情应该工作：

Ok, at least something like this should work:

instance_id=$(ec2-run-instances ami-dd8ea5a9 [...] | awk '/INSTANCE/{print $2}') 

诚然我是有点懒的思维，它是更快地问就因此比重新学习一些基本的AWK ...： - ）

Admittedly I was a bit lazy thinking that it's quicker to ask on SO than to relearn some AWK basics... :-)

修改：简化AWK用法丹尼斯建议。此外，使用 $（），而不是``为了清楚起见，并摆脱了中间变量。

Edit: simplified AWK usage as Dennis suggested. Also, using $() instead of `` for clarity, and got rid of intermediate variable.