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docker - exec形式的Docker RUN命令不起作用

问题描述

我正在构建一个基于 Alpine 的 docker 镜像。

FROM alpine

RUN apk update \
    && apk add lighttpd \
    && rm -rf /var/cache/apk/*

ENV COLOR red

COPY ./index.html /var/www/localhost/htdocs

RUN /bin/ash -c 'echo abcd'
#working
RUN /bin/ash -c "echo $COLOR; sed -i -e 's/red/\$COLOR/g' /var/www/localhost/htdocs/index.html; cat /var/www/localhost/htdocs/index.html;"
#not working
# RUN ["sh", "-c", "echo $COLOR; sed -i -e 's/red/\$COLOR/g' /var/www/localhost/htdocs/index.html; cat /var/www/localhost/htdocs/index.html;"]

CMD ["lighttpd","-D","-f","/etc/lighttpd/lighttpd.conf"]

当我以 shell 形式运行时，它工作正常，但是当我以 exec 形式运行时，它给出了

/bin/sh: [sh,: 未找到

我尝试使用bin/sh, sh, bin/ash, ash. 他们所有人都犯了同样的错误。

标签： dockeralpine

解决方案

Shell 负责扩展变量，但只有双引号中的变量才会被扩展。

您的错误来自\之前的错误$COLOR，实际上您从shell中获取值没有任何意义，正确的方法是下一个：

RUN ["sh", "-c", "echo $COLOR; sed -i -e \"s/red/$COLOR/g\" /var/www/localhost/htdocs/index.html; cat /var/www/localhost/htdocs/index.html;"]

显示效果的最小示例，仅供参考：

Dockerfile：

FROM alpine
ENV COLOR rednew
RUN echo "red" > /tmp/index.html
RUN ["sh", "-c", "sed -i -e \"s/red/$COLOR/g\" /tmp/index.html; cat /tmp/index.html;"]

结果：

$ docker build -t abc:1 . --no-cache                                                                                              
Sending build context to Docker daemon  5.632kB
Step 1/4 : FROM alpine
 ---> 28f6e2705743
Step 2/4 : ENV COLOR rednew
 ---> Running in 05c43146fab0
Removing intermediate container 05c43146fab0
 ---> 28ea1434e626
Step 3/4 : RUN echo "red" > /tmp/index.html
 ---> Running in 2c8fbbc5fd10
Removing intermediate container 2c8fbbc5fd10
 ---> f884892ad8c4
Step 4/4 : RUN ["sh", "-c", "sed -i -e \"s/red/$COLOR/g\" /tmp/index.html; cat /tmp/index.html;"]
 ---> Running in 6930b3d03438
rednew
Removing intermediate container 6930b3d03438
 ---> b770475672cc
Successfully built b770475672cc
Successfully tagged abc:1

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