short yum - is a package manager for linux (centos, redhat)

• search file installed from which rpm

• delete old kernel packages (keep latest)
  • CentOS 6/7:

    package-cleanup --oldkernels --count=1

  • CentOS 8:

    dnf remove $(dnf repoquery --installonly --latest-limit=-1 -q)

    or

    dnf remove --oldinstallonly --setop installonly_limit=2 kernel

warning: Signature not supported. Hash algorithm SHA1 not available.

RedHat has disable SHA1 support for signing rpms, so if you want to install do the following before (and dont forget after):

1. update-crypto-policies --set DEFAULT:SHA1

2. dnf install oldapp.rpm

3. update-crypto-policies --set DEFAULT

Info: https://www.redhat.com/en/blog/rhel-security-sha-1-package-signatures-distrusted-rhel-9