Skip already-installed packages in "yum install"?

Question

It seems that if a package is already installed, "yum install" will try to update it to the latest version. This will cause "yum install" to fail if the latest version is missing dependencies. I know that I can suppress this with --skip-broken, but I don't want to "skip broken" in case of packages which are not already installed; in that case I want it to fail.

I have seen in this answer that I can do this using an "if" statement if I am installing just one package, but I have a "yum install" statement containing some 15 packages, and don't want to run yum multiple times (once for each package) as this adds a lot of overhead.

How can I get yum to only install packages if they are not already present?

Answer 1

In the end I wrote a simple bash script yum-install-if-missing.sh based on other answers. Not sure if there is an easier way.

#!/bin/bash

yumcmd="yum install -y"
for var in "$@"
do
    if ! rpm --quiet --query $var; then
        yumcmd="$yumcmd $var"
    fi
done

echo "ABOUT TO EXECUTE: $yumcmd"

eval $yumcmd

It can then be executed as: yum-install-if-missing.sh packageone packagetwo and so on.