10 Practical Examples of RPM Commands in Linux

In this post, I will explain you the usage of RPM (Red Hat Package Manager) command with an example. RPM commands are widely used in Linux operating system to install, remove or update the packages on operating system.

RPM (Red Hat Package Manager) is a default open source and package management utlity which is widely used on Redhat, CentOS linux operating system. You can install , remove, upgrade the packages using this commnad. In this post We will explain each syntax with an example so you can understand how this command is very useful on linux operating system. So here, we will explain best 20 example which is related to Red Hat Package Manager.

1. How to Check an RPM Signature Package:

This command with syntax is used for to check the PGP signature of packages before installing them on your Linux systems and make sure its integrity and origin is fine.

[root@locahost]# rpm --checksig vsftpd-2.2.2-14.el6.x86_64.rpm

vsftpd-2.2.2-14.el6.x86_64.rpm: rsa sha1 (md5) pgp md5 OK

2. How to Install an RPM Package:

Using below syntax you can install the rpm packages on the linux system.

[root@localhost]# rpm -ivh vsftpd-2.2.2-14.el6.x86_64.rpm

Preparing...               ########################################### [100%]

1:vsftpd                    ########################################### [100%]

On the above syantx we are using "-i" option to install the rpm packages on Linux operating system.

3. How to check dependencies of RPM Package before Installing:

If you want to check which packages or dependency is required for RPM packages then you can run the below command to check the dependency.

[root@localhost]# rpm -qpR samba-winbind-3.6.23-12.el6.x86_64.rpm

Here, you can find the syantx meaning of the above command.

-q : Query a package.

-p : List capabilities this package provides.

-R: List capabilities on which this package depends.

4. How to Install a RPM Package Without Dependencies:

If you want to install the packages without any dependency please use the below syntax.

[root@localhost]# rpm -ivh --nodeps samba-winbind-3.6.23-12.el6.x86_64.rpm

Preparing...                       ########################################### [100%]

1:Samba-winbind             ########################################### [100%]

The above command forcefully install rpm package by ignoring dependencies errors, but if those dependency files are missing, then the program will not work at all, until you install them.

5. How to check an Installed RPM Package:

If you want to check which RPM package is installed on the operating system then please use -q option with package name.

[root@localhost]# rpm -q samba

package samba is not installed

If you see the samba packages is not installed on my system so it is show you this message.

[root@localhost]# rpm -q vsftpd

vsftpd-2.2.2-14.el6.x86_64

You can see the above ftp server packages is installed on the system.

6. How to Upgrade a RPM Package:

If you want to upgrade any RPM packages then please use "-U" syntax with rpm name.

[root@localhost]# rpm -Uvh vsftpd-3.0.2-11.el6.x86_64.rpm

Preparing...             ########################################### [100%]

1:vsftpd                 ########################################### [100%]

If you see the above example the packages is upgrade with the new version of vsftpd.

7. How to Remove a RPM Package:

If you want to uninstall or remove the package from the server then please use "-e" erase option is used to remove package.

[root@localhost]# rpm -evv vsftpd

Using above command we can remove the packages with all dependency.

8. How to Remove an RPM Package Without Dependencies:

If you want to remove installed packages without any dependecy then use the below syntax to remove the rpm.

[root@localhost]# rpm -ev --nodeps vsftpd

Using above syntax "--nodeps" we can remove the packages without dependency.

9. How to Import an RPM GPG key:

If you want to import the RPM GPG key then please verify RHEL/CentOS/Fedora packages, you must import the GPG key.

[root@localhost]# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

So using above syantx we can import the GPG key on the server.

10. How to List all Imported RPM GPG keys:

To print all the imported GPG keys in your system, use the following command.

[root@localhost]# rpm -qa gpg-pubkey*

gpg-pubkey-0608b895-4bd22942

gpg-pubkey-7fac5991-4615767f

You can see the above entry these are the GPG key which is installed on the server.

Step by Step Configuration of NTP Server on HP-UX Server

In this post, I would like to explain how we configure the NTP (network time protocol) server on HP-UX operating system server. In my recent post you can found the NTP configuration on Solaris and AIX platform. 

As you know NTP ( Network time Protocol) is one of the oldest internet protocol still in use and it allows the synchronization of computer clocks distributing UTC (Coordinated Universal Time) over the network. It is basaiclly used for time synchronization on Unix servers.

Step by Step Configuration of NTP Server on HP-UX:

1. In the first step we will check the configuration files of "xntpd" daemon. By default the configuration file for this daemon is "/etc/rc.config.d/netdaemons".

# vi /etc/rc.config.d/netdaemons

######################################

# xntp configuration.  See xntpd(1m) #

######################################

#

#  Time synchronization daemon

#

# NTPDATE_SERVER: name of trusted timeserver to synchronize with at boot

# (default is rootserver for diskess clients)

# XNTPD:        Set to 1 to start xntpd (0 to not run xntpd)

# XNTPD_ARGS:  command line arguments for xntpd

#

# Also, see the /etc/ntp.conf and /etc/ntp.keys file for additional

# configuration.

#

export NTPDATE_SERVER=

export XNTPD=0

export XNTPD_ARGS=

This is default configuration entry of this file so for xntpd daemon we need to change the variable which is defined.

export NTPDATE_SERVER='ntp.in.pool.org'

export XNTPD=1

export XNTPD_ARGS=

Note: You must change the NTPDATE server name.

2. For ntp config please set the correct timezone is setup in /etc/TIMEZONE file.

hpx:/> cat /etc/TIMEZONE

TZ=IST-5:30

export TZ

You can edit the file in vi editor and change the time zone as per your location.

3. Now, we need to make some changes in NTP configuration files. 

hpx29:/> cat /etc/ntp.conf

#Configuration NTP des serveurs

server ntp.in.org.com

server ntpin.in.org.com

You need to replace ntp server name accordingly. In my post I will use dummy server name.

4. After setting the NTP server name we need to restart the NTP service on HP-UX operating system and verify the ntp configuration.

hpx:/> /sbin/init.d/xntpd restart

hpx:/> ntpq -p

If it is showing you correct ntp server information now. You can match these information with the NTP server name which we use in above step.

How to configure NTP Server on AIX Operating system

In the last post, I had explained the NTP (Network Time Protocol) on Solaris 10 & 11 server. Now in this post, I will explain the same NTP server and client configuration for AIX operating system.

As you know NTP ( Network time Protocol) is one of the oldest internet protocol still in use and it allows the synchronization of computer clocks distributing UTC (Coordinated Universal Time) over the network.

Step by Step Configuration of NTP:

1. In the initial step we must verify that we have check the available NTP server on AIX server. For this please run the below command.

AIX:/>lssrc -ls xntpd

-----------------------------------------------

 Program name:    /usr/sbin/xntpd

 Version:         3

 Leap indicator:  00 (No leap second today.)

 Sys peer:        ntp.aix.in.com

 Sys stratum:     4

 Sys precision:   -18

 Debug/Tracing:   DISABLED

 Root distance:   0.014709

 Root dispersion: 0.066422

 Reference ID:    192.168.1.22

 Reference time:  dc721077.d3a8e000  Tue, Mar 14 2017  7:47:19.826

 Broadcast delay: 0.003906 (sec)

 Auth delay:      0.000122 (sec)

 System flags:    pll monitor filegen

 System uptime:   19248381 (sec)

 Clock stability: 0.000107 (sec)

 Clock frequency: 0.000000 (sec)

 Peer: ntp.aix.in.com

      flags: (configured)(sys peer)

      stratum:  3, version: 3

      our mode: client, his mode: server

 Peer: ntpuk.aix.in.com

      flags: (configured)(sys peer)

      stratum:  3, version: 3

      our mode: client, his mode: server

Subsystem         Group            PID          Status

xntpd            tcpip            8520514      active

------------------------------------------------------

You can found the above output once you run the above command to check the available NTP server. On my AIX machine if you see the sys peer should show a valid server (ntp.aix.in.com). If the server is not showing any ntp server then we need to correct it by adding a server line into /etc/ntp.conf and will take restart of "xntpd" services.

Note : In this post I will use my dummy NTP name instead of real NTP server because of security reason.

2. As your NTP server is not configured and it is show "insame" then you need to add manual entry on the NTP configuration file.

AIX:/>vi /etc/ntp.conf

server ntp.aix.in.com

server ntpuk.aix.in.com

Once you added these ntp server entry manually on the configuration file then please take a restart of NTP services.

AIX:/>stopsrc -s xntpd

AIX:/>startsrc -s xntpd

Using above command we can stop and start the "xntpd" service on AIX operating system.

3. In this step you need to again verify the status of newly added NTP server.

AIX:/>lssrc -ls xntpd

It is taking some time that time because it synchronize process is running. Once the synchronization has been complete and you run the above command you can found the NTP server entry as describe in Step 1.

Step by Step configuration of NTP Client:

1. On the client machine you need to again verify that you have a server suitable for synchronization or not. For this please run the below command.

AIX:/>ntpdate -d ntp.aix.in.com

-----------------------------------------------------------

14 Mar 08:16:21 ntpdate[64356890]: 3.4y

transmit(192.168.1.22)

receive(192.168.1.22)

transmit(192.168.1.22)

receive(192.168.1.22)

transmit(192.168.1.22)

transmit(192.168.1.22)

transmit(192.168.1.22)

server 192.168.1.22, port 123

stratum 16, precision -6, leap 11, trust 000

refid [63.15.23.11], delay 0.03688, dispersion 24.00334

transmitted 4, in filter 4

reference time:      00000000.00000000  Thu, Feb  7 2036  7:28:16.000

originate timestamp: dc721745.3ff1b000  Tue, Mar 14 2017  8:16:21.249

transmit timestamp:  dc721746.3d08a000  Tue, Mar 14 2017  8:16:22.238

filter delay:  0.03688  0.05624  0.00000  0.00000

               0.00000  0.00000  0.00000  0.00000

filter offset: -0.00081 -0.00750 0.000000 0.000000

               0.000000 0.000000 0.000000 0.000000

delay 0.03688, dispersion 24.00334

offset -0.000812

14 Mar 08:16:23 ntpdate[64356890]: no server suitable for synchronization found

--------------------------------------------------------------------------

If you get the message ," no server suitable for synchronization found", verify xntpd is running on the server also verify that no firewalls are blocking port 123.

2. If the no server suitable for synchronization then you must specify the xntpd server in /etc/ntp.conf.

AIX:/>vi /etc/ntp.conf

server ntp.aix.in.com

Once you added the NTP server entry on client configuration file then restart the "xntpd" service again.

AIX:/>startsrc -s xntpd

3. If you want to start the xntpd service on boot time then you need to uncomment the below lines on the configuration file.

AIX:/>vi /etc/rc.tcpip

Unconmment the following line

start /usr/sbin/xntpd "$src-running"

4. Now verify the NTP server on client machine has been synchronized or not. Please use the same command which we used for checking the status.

AIX:/>lssrsc -ls xntpd

This time on the NTP client machine sys peer should display the IP Address or name of your "xntpd" server. As you know it is taking some time to synchronization so you must wait for time.

How to disable the SELinux in Linux machine

In this post, I will explain you the how to disable SELINUX on Redhat or CentOS Operating system. Before going to main work first we need to understand what is SELINUX and how its work on Linux enviorement.

Security-enhanced Linux (SELINUX): SELinux is know as Security enhanced linux system which is the security feature of the Linux kernel system. It is define the security Policy which makes system proctative agaginst the misconfiguration of the daemons. SELinux running in 3 modes which is disabled, enabled and permissive. We will explain these mode in configuration steps.

How to disable SELinux on Linux system:

1. In the first step you can check the current status of SELinux. To do this please run the below command.

[redhat]# getenforce

Enabled

"getenforce" command is used for checking the current status of SELinux.

2. As you see on my machine when I run the above command my SElinux is enabled, So in this step we will change the SELinux mode.

[redhat]# vi /etc/sysconfig/selinux

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

#     enforcing - SELinux security policy is enforced.

#     permissive - SELinux prints warnings instead of enforcing.

#     disabled - No SELinux policy is loaded.

SELINUX=disabled

# SELINUXTYPE= can take one of these two values:

#     targeted - Targeted processes are protected,

#     mls - Multi Level Security protection.

SELINUXTYPE=targeted

Normally selinux configuration file you can found on the above location. You can edit the SELINUX entry to disabled. All the command is run by super user "root" only.

3. Once you change the entry in SELinux configuration file then for permanent effect you need to take a reboot of the system.

[redhat]#init 6

Once you reboot the server all the configuration files changes has been done.

4. In the last step you will run the "getenforce" command again to verify the new status of SELinux.

[redhat]# getenforce

Disabled

If you comparison the both step 1 and this step output you can found that SELinux policy is not disabled on the Linux operating system.

How to mount CIFS file system on Linux Server

Hope you are doing well at your end. In this post, I will explain how we mount the CIFS file system on Linux operating system.

Normally on linux machine if we mount the any other linux machine folder is quite easiy in comparision to mount the window shared folder on linux machine. So let's going to final topic where i will explain step by step method to mount the CFS folder on Linux server.

Step by Step method for Mount CIFS on Linux Server:

1. In the initial step we will gather all rpm's or packages information which is required for CIFS file system.

redhat# rpm -qa | grep cifs 

cifs-utils-4.8.1-20.el6.x86_64

if you see the above output, this packages is required for CIFS file system on Linux system. So you can install this rpm using rpm command if you have rpm packages on the server otherwise you will install the packages using YUM utility.

redhat#rpm -ivh cifs-utils-4.8.1-20.el6.x86_64.rpm

if you are using YUM, then please install the packages using below command.

redhat#yum install cifs-utils*

it is installed all required dependency related to CIFS file system.

2. In this step, we will create the mount point on the server where we need to mount the CIFS file system.

redhat# mkdir -p /backup/cifs

We will create the above mount directory where i will mount the file system.

3. Now, we will create a CIFS user and assign a password so the user can access mount folder.

redhat# touch /etc/cifspasswd

redhat# chmod 600 /etc/cifspasswd

redhat#vi /etc/cifspasswd

user=castwebsvc

password=*******

4. In this step we need to make a permanent entry of mounted file system so once we reboot the machine mounted file system not umount.

redhat# vi /etc/fstab

ADD fstab entry :

//WindowsServer/share /mount/point cifs rw,mand,user=USER,password=PASS 0 0

Example :

//192.168.0.1/CAST_data4/AICCodeUpload  /backup/cifs cifs   rw,mand,credentials=/etc/cifspasswd         0 0

You can take an example for your system. Please change the mount point as per your requirement.

5. In the final step you need to mount the file system using below command.

redhat# mount /backup/cifs

redhat# mount -a

Using above command the CIFS file system has been mounted successfully.

How to configure NTP server and client on Solaris 10 and Solaris 11

In this post, I will describe the step by step method that how we will configure the NTP server and client on Solaris 10 and Solaris 11 Operating system. Network time protocol is most important part of any UNIX operating system. We will setup the NTP daemon on both the operating system but before moving to main point we will understand first NTP mechanism.

As you know NTP ( Network time Protocol) is one of the oldest internet protocol still in use and it allows the synchronization of computer clocks distributing UTC (Coordinated Universal Time) over the network.

NTP Service on Solaris 10 and Solaris 11:

Solaris 10 used the SMF utility (Service Management Facility) and the NTP service is now managed by SMF (Service Management Facility). NTP daemon configured using Service management facility (svc:/network/ntp:default) and a bunch of sample ntp.conf files to quickly configure a machine as a client or as a server. On Solaris 11 only ships with NTP v. 4, the NTP v. 4 service is identified by the name ntp4. You can check the ntp status using below command.

sun# svcs status ntp

STATE  STIME   FMRI

online 10:14:23 svc:/network/ntp:default

If you see the above command output it is shown that network time protocol services is enable and online on the server.

Steps for Configuring a NTP client:

Suppose your machine is just a client machine, then you can just take the /etc/inet/ntp.client file and copy it to /etc/inet/ntp.conf.

multicastclient 127.0.0.1

If you see the configuration it's a passive configuration for a Server host which listens for NTP server putting packets on the NTP multicast network, 127.0.0.1. If your machine is on LAN without NTP server then in that case we are not recveied any packet and for this we need to use Public NTP server for host.

In my case, I'm using the Indian pool in.pool.ntp.org and my configuration file contains:

server 2.in.pool.ntp.org

server 1.asia.pool.ntp.org

server 3.asia.pool.ntp.org

Normally NTP requires a poll period to elapse before starting synchronizing your clock. If you want NTP to start immediately, which you most probably will if you're configuring a desktop environment, you can take advantage of iburst keyword, introduced in NTP v. 4: it instructs NTP to start the synchronization almost right away.

server 2.in.pool.ntp.org ibrust

server 1.asia.pool.ntp.org ibrust

server 3.asia.pool.ntp.org ibrust

You must make sure you're configuring NTP implementation corresponding to the syntax you're using.

Setting up the drift file:

The last thing which is remaining for NTP server setup in the client machine is to set up  drift file location. On my machine it is 

driftfile /var/ntp/ntp.drift

After setup the drift file configuration we will start the NTP servivce again 

sun# svcadm restart svc:/network/ntp:default

sun# svcs status svc:/network/ntp:default

STATE  STIME   FMRI

online 12:20:12 svc:/network/ntp:default 

Once the service is running, you can check which server you're using with ntpq, Please run the below command to check the ntpq.

sun# ntpq -p

Setting up an NTP server:

Now in above step you see the NTP service has been started successfully, so now, you'll probably want to setup all of your machines.

If you're in a LAN, you can setup an internal NTP server which will provide data to other clients on your LAN. As before, you can take inspiration from the server configuration file shipped with Solaris 10 or Solaris 11, /etc/inet/ntp.server.

After setting up the drift file and the clients you're going to use, you can examine the other options and fine-tune them at your taste. Let's give a quick look at it.

server 127.127.XType.0

Now you have configured the NTP server properly. Please comment on the post if you have any suggestion.

Solaris Package administration in Solaris 10

In this post, we will get the knowledage about the package administartion on Solaris operating system. As you aware that on solaris server the packages administration work is quite different from other Unix operating system. Solaris system has different architecture for this one.

So, we will discuss first which command is generally used on Solaris 10 server which are listed below.

pkginfo- It displays all software package information.
pkgadd- It installs all software packages to the system.
pkgrm- It removes a package from the system.
pkgchk- It checks package installation state.
pkgtrans- It translates packages from one server format to another.

Commands & Syntax for checking a package information:

For checking a packages information on Solaris 10 operating system we will used the "pkginfo" command. You can find the all command and syntax related to "pkginfo" is listed below.

• Please use the below command to display information about installed software packages.

          sun# pkginfo | more

• Please use the below command to view additional information.

          sun# pkginfo -l | more

• Please use the below command to view information of a specific package.

          sun# pkginfo -l SUNWman

• Please use the below command to find how many packages are currently installed.

          sun# pkginfo | wc -l

• To list all installed software packages, please use the below command.

          sun# more /var/sadm/install/contents

These above commands with their syntax are daily used on Solaris 10 platform.

Commands & Syntax for checking a package installation:

For checking an information about packages are installed or not on the server , we need to use "pkgchk"  command. Please find the below example as describe below.

• Please use the below command to check the contents & attributes of a currently installed package.

          sun# pkgchk SUNWpkgs

• Please use the below command to list the all files contained in a software package.

          sun# pkgchk -v SUNWpkgs

• Please use the below commands to find if the contents & attributes of a file have changed since it was installed with its software package.

          sun# pkgchk -p /etc/shadow  

• Please use the below commands to list information about selected files that make up a package.

          sun# pkgchk -l -p /usr/bin/showrev

If the packages is installed already then in that case "pkgchk" command don't show any output that clear meaning is that packages is already installed on the server.

Commands & Syntax for adding a package software:

For adding a packages on the server, we will used the "pkgadd" command. Please find the below commands and their syntax which is daily used on Solaris operating system.

• Please use the below command to add a software packages from DVD. For this you need to move on dvd directory where all the packages are listed.

          sun# pkgadd -d . SUNWpkgs

Using above command you can add the packages from DVD.

Commands & Syntax for removing a package software:

For removing the packages from the server, we will used "pkgrm" command. Please find the below commands and their syntax as listed below.

• Please use the below command to remove the software packages.

          sun# pkgrm SUNWpkgs

• Please use the below command to remove a package from the spool directory.

          sun# pkgrm -s /export/pkg SUNWldam

Commands & Syntax for translating a packages format:

For translating a packages format from one format to another , we will used the "pkgtrans" command for the same.

• Please use the below command to translate a package from file system format in /var/tmp to data stream format.

          sun# pkgtrans /var/tmp /tmp/SUNWpkgs.pkg SUNWpkgs

• Please use the below command to create a data streamed package.

          sun# pkgtrans -s Product /var/tmp/stream.pkg SUNWpkgg SUNWpkgs

 Using above commands and synatx we can easily translate their file format to stream format. If you have any doubt regarding this post please comment on the post.