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Logrotate is a system utility that manages the automatic rotation and compression of log files. 1 2 logrotate --version man logrotate Configuration can be found generally in two places: /etc/logrotate.conf: contain some default settings, sets up rotation for a few logs that are not owned by any system packages. Also uses an include statement to pull in configuration from any file from the logrotate directory. /etc/logrotate.d: files for packages. By default, logrotate.confwill configure weekly log rotations, with log files owned by the root user and the syslog group., with four log files being retained at a time (rotate 4) and new empty log files being created after the current one is rotated (create). ...

jounralctl is the command line tool that let us interact with the journal logs. Default location of journald logs is /var/log/journal directory. Type journalctl in the terminal, it will show the journal logs in chronological order. journalctl --no-pager will display entire logs directly on the screen. journalctl -n 25: will display most recent 25 lines of the logs. journalctl -f: view logs in real time. jouralctl --utc: display logs in UTC time. journalctl -k: display only kernel logs. All Journal logs Use sudo to see all journal logs. ...

Service management 1 2 3 4 5 6 7 8 9 10 11 12 13 sudo systemctl start app.service sudo systemctl stop app.service sudo systemctl restart app.service sudo systemctl reload app.service sudo systemctl reload-or-restart app.service sudo systemctl enable app.service sudo systemctl disable app.service Checking status 1 2 3 4 5 6 7 systemctl status app.service systemctl is-active app.service systemctl is-enabled app.service systemctl is-failed app.service System state overview 1 2 3 4 5 6 7 8 9 10 # see a list of active units systemctl list-units systemctl # returns same as above systemctl list-units --all systemctl list-units --all --state=inactive systemctl list-units --type=service To see every available units in the system paths (including those that systemd has not attempted to load): ...

As I am highly dependent on official documentation, I found that Apache Solr maintain an awesome documentation from which I learned a lot. Setting up SSL can be found here. I am writing this for easier step by step setup. Happy Searching! Generate certificate & key From the official documentation, you can generate a self-signed certificate to test your setup. But for the trusted authority, generate a certificate and convert it to .pfx format, which is type PKCS12. ...

man - display a program’s manual page. 1 man program # program is the name of the command On most Linux systems, man uses less to display manual page. The manual that man displays is broken into sections and covers not only user commands but also system administration commands, programming interfaces, file formats and more. Man page organization: Section Contents 1 user commands 2 programming interfaces for kernel system calls 3 programming interfaces to the C library 4 special files such as device nodes and drivers 5 file formats 6 games and amusements such as screen savers 7 Miscellaneous 8 System administration commands 9 Obscure kernel specs and interfaces 1 2 3 man section search_item man 5 passwd Refer to a specific section of the manual to find what we are looking for. ...

I wasn’t familiar with SolrCloud when I started working with this. When I started to learn it and working directly with it - I had done so many mistakes. Even setting up SolrCloud for production was a hassle for me (I’m a slow learner). But overtime, I got a hang of it and I think writing an up-to-date guide to set up SolrCloud on production server is a good idea. ...

When I wanted to customize my GitHub profile, I visited many developers’ GitHub profiles. I saw some badges which seemed cool to me. When I looked at the code behind the shapes, I didn’t know what was happening. Later, I tried to copy some of the code and paste them into my code, but it couldn’t solve the need. After some reading and searching, I understood how to make them. I am writing this post as a reference so that one can understand how to make those badges, including me. ...

In my Computer Graphics class, the teacher asked us to setup Codeblocks for the glut. She gave us a tutorial on how to setup Codeblocks on windows but didn’t provide any suggestion to set up on Linux. After some searching on google, I was able to setup Codeblocks with Freeglut (which is an alternative to Glut and available on Linux). This is a kind of writeup (or tutorial) on how I was able to setup Codeblocks with Freeglut. ...