Author: Seyed Vahid Hashemi

  • After configuring Ubuntu to use LDAP ssh login become too slow

    This is a common symptom of mis behaviour of systemd-logind. I couldn’t still find-out what is really happening underneath of this service but if you experience such issues you can try to restart the service using following command sudo service systemd-logind restart and make sure to run this code on the console not just by […]

  • How to install maven on Ubuntu manually with any specific version

    For installing Maven on Ubuntu you have two ways  the easy way and the manual method. The easy way is just execute following command : sudo apt-get install maven Or if you use Ubuntu 16+ you can use following command too : sudo apt install maven Just remember you need to have root privileges. The […]

  • How to traceroute a particular IP and Port?

    There are sometimes that you want to trace an IP/Host based on a particular port to check if the port is open or not here is how you can do that : traceroute -T -p 25 Breakdown : -T indicates to use TCP instead of UDP -p checks specific port Seyed Vahid HashemiMy chief […]

  • How to install JDK on Ubuntu

    Installing Java JDK is easy and straightforward in Windows and OSX but not in Ubuntu. Here is how I am installing JDK on Ubuntu. Download the latest JDK package from Oracle website. If you don’t know which file to choose you ought to select .tar.gz files whether 32bit or 64bit depends on your requirements. after […]

  • What does $? mean in linux?

    The $? is called exit code of an application used to run. As an example type following commands in console: top then press CTRL-Z and then type: echo $? You will see 147 as the answer. Return values more than 128 usually means signal and you have to do the calculation by subtracting 128 from […]