We will explain the options that can be added to the
rpm command (Redhat Package Manager) in order to query packages in Linux. The following elements of the article will be explained:
- How to query the whole RPM database?
- How to identify the specific package by using grep?
- How to query a file?
- How to query various files of this package?
- How to list only the configuration files?
- How to list only documentation files?
- How to restore configuration file from RPM package?
1) How to query the whole RPM database
To query the whole RPM database, we will use
-qa option (query all) to displays all the installed packages in Linux.
$ sudo rpm -qa
Output grub2-tools-extra-2.02-0.65.el7.centos.2.x86_64 ncurses-base-5.9-14.20130511.el7_4.noarch libpipeline-1.2.3-3.el7.x86_64 kbd-misc-1.15.5-13.el7.noarch tuned-2.9.0-1.el7.noarch bash-4.2.46-30.el7.x86_64 info-5.1-5.el7.x86_64 ...
2) How to identify the specific package by using grep
We will use
grep to shows other packages related to
ssh but we have to still identify that which package is actually installing SSH.
$ rpm -qa | grep ssh
output openssh-clients-7.4p1-16.el7.x86_64 openssh-7.4p1-16.el7.x86_64 openssh-server-7.4p1-16.el7.x86_64 libssh2-1.4.3-10.el7_2.1.x86_64
3) How to query a file
ssh from the
openssh-server-5.3p1-84.1.el6.x86_64 package. We can use
-qf option (query file) with rpm command on a configuration file. The output is the RPM package that installed from.
$ rpm -qf /etc/ssh/sshd_config
4) How to query various files of this package
We will use
-ql option with
rpm command to show all the files of this installed package on the system.
$ rpm -ql openssh-server-7.4p1-16.el7.x86_64
output /etc/pam.d/sshd /etc/ssh/sshd_config /etc/sysconfig/sshd /usr/lib/systemd/system/sshd-keygen.service /usr/lib/systemd/system/sshd.service /usr/lib/systemd/system/sshd.socket /usr/lib/systemd/system/[email protected] /usr/lib64/fipscheck/sshd.hmac /usr/libexec/openssh/sftp-server /usr/sbin/sshd /usr/sbin/sshd-keygen /usr/share/man/man5/moduli.5.gz /usr/share/man/man5/sshd_config.5.gz /usr/share/man/man8/sftp-server.8.gz /usr/share/man/man8/sshd.8.gz /var/empty/sshd
5) How to list only the configuration files
We will use
-qc option with
rpm command to displays configuration file related to package.
$ rpm -qc openssh-server-7.4p1-16.el7.x86_64
output /etc/pam.d/sshd /etc/ssh/sshd_config /etc/sysconfig/sshd
6) How to list only documentation files
We will use
-qd option (query documentation) with
rpm command to list only documentation files.
$ rpm -qd openssh-server-7.4p1-16.el7.x86_64
output /usr/share/man/man5/moduli.5.gz /usr/share/man/man5/sshd_config.5.gz /usr/share/man/man8/sftp-server.8.gz /usr/share/man/man8/sshd.8.gz
7) How to restore configuration file from RPM package
If for some reason a file has been damaged or got deleted from the system, we can start with the
rpm -qf query option to find out from what package the file originated. Next use
rpm2cpio | cpio -idmv to extract the files from the package. Consider the ssh example:
Assuming that the
/etc/ssh/sshd_config file has been deleted and we may not want to reinstall ssh, so we will restore the file using the steps below.
- The below command shows that the file comes from the openssh-server-7.4p1-16.el7.x86_64 Package.
$ rpm -qf /etc/init.d/sshd
- Download the Openssh rpm from it's source
openssh-server-7.4p1-16.el7.x86_64package file to
/tmpdirectory or any other directory of your choice.
rpm2cpio | cpio -idmvto extract the package.
The commands we used in the above steps created a few sub directories in
/tmp. We can now copy it to its original location.