静默检查bash脚本中是否存在rpm [英] Check if rpm exists in bash script silently

问题描述

我正在尝试使用if语句快速检查bash脚本中是否安装了rpm.但是我想安静地做.当前，当我运行脚本并且确实存在rpm时，它将rpm的输出输出到我不想要的屏幕上.

I'm trying to do a quick check to see if an rpm is installed in a bash script using an if statement. But I want to do it silently. Currently, when I run the script, and the rpm does exist, it outputs the output of rpm to the screen which I dont want.

if rpm -qa | grep glib; then
    do something
fi

也许我错过了一个rpm选项?还是只需要更改我的声明?

Maybe there is an option to rpm that I am missing? or if I just need to change my statement?

谢谢

推荐答案

1)您可以将-q开关添加到grep

1) You can add -q switch to grep

if rpm -qa | grep -q glib; then
  do something
fi

2)您可以将stout和/或stderr输出重定向到/dev/null

2) You can redirect stout and/or stderr output to /dev/null

if rpm -qa | grep glib  2>&1 > /dev/null; then
  do something
fi

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