如何在Makefile中运行子Shell脚本? [英] How to run sub Shell script in Makefile?

问题描述

我想执行Shell命令，但是我不知道如何在我的Makefile中正确执行sub bash命令

I want to execute a Shell command but I didn't know how to do a sub bash command correctly in my Makefile

import-bd:
    @while ! nc -z $(make ips | awk '/mysql/ { print $2 }') 3306; do \
        sleep 1 \
    done
    ...

感谢您的帮助！

推荐答案

您需要引用$并添加;

import-bd:
    @while ! nc -z $$(make ips | awk '/mysql/ { print $$2 }') 3306; do \
        sleep 1; \
    done

当make看到单个$时，它将尝试进行变量扩展.通过编写$$，make将单个$传递给awk(或更准确地说，将单​​个$传递给调用awk的SHELL).另外，需要使用sleep 1后的分号，因为make会删除换行符.

When make sees a single $, it tries to do a variable expansion. By writing $$, make passes a single $ to awk (or, more precisely, it passes a single $ to SHELL which invokes awk). Also, the semi-colon after sleep 1 is needed because make strips the newline.

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