有没有正确的方法来解析命令中Bash的输出? [英] Is there a correct way to parse output in Bash from a command?

问题描述

我正在使用psql运行一些命令，其中最后一个类似于:select max(id) from tablename.我正在尝试获取插入的最后一行的ID.在这种情况下，它将返回正确的值(7).

I'm using psql to run a few commands, where the last one is something similar to: select max(id) from tablename. I'm trying to get the id of the last row inserted. It returns the correct value (7) in this scenario.

Begin Informatica Script SET INSERT 0 1 max ----- 7 (1 row) Redshift Delta copy completed at: 04/10/17 17:45:21 END

但是，我正在尝试解析它，却不知道该怎么办...是否有办法将输出限制为仅7的值?如果没有，我该如何获取号码?也有可能成为一个很大的数字，例如10,000

However, I'm trying to parse it and have no idea what to do... Is there a way to limit the output to just the value of 7? If not, how do I grab just the number? There is the possibility of this becoming a rather large number as well, like 10,000

我添加了2个选项-qt，并将输出降低到:

I added 2 options -qt and got the output down to:

Begin Informatica Script 9 Redshift Delta copy completed at: 04/10/17 17:53:53 END

在这种情况下，9是我想要的ID.

In that, 9 is the ID I want.

推荐答案

使用GNU sed:

echo 'Begin Informatica Script 9 Redshift Delta copy completed at: 04/10/17 17:53:53 END' | sed -r 's/.*Begin Informatica Script ([0-9,]+) Redshift Delta.*/\1/'

输出:

9

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