When analyzing the output of a bash script, it can be useful to prepend timestamp before each line to see how long it’s taking to do a specific action.

For this, you can use the ‘ts‘ command:

If the command ‘ts‘ is not available, you might need to install the package moreutils.

Seeing that error in HTTPd/Apache logs when trying to GET some pages?

This is because of some SELinux policies blocking the calls. If you don’t want to turn SELinux off, a simple workaround is:

When updating or installing a package on a Debian-based distribution, you can face that alert:

This just means that a signing GPG key is missing or expired on your system. The error is giving you the ID of the missing key that you can use for looking for it on the Ubuntu website:

Copy the key that you just got from the website above into a file – mykey.txt, for example – and import it with the apt-key command:

Try to install/update the package again, and the error should not appear anymore.

The PKCS12 format is replacing the old PFX format from Microsoft. This format will allow storage of X.509 private keys and the associated public certificates in a single encrypted file.

So you can extract the key and the certificate in a single common PEM file, you can use this openssl command:

If you want to extract the key and the certificate independently, you can also use the options nocerts/nokeys along with openssl, to extract only one part:

When doing update on a Debian/Ubuntu server, if a package is trying to modify a config file, it’s asking for a manual choice. If you’re trying to try to automate the process, you’d probably like to get rid of that ask and keep the current config file by default.

For that, you can use that script:

The multiple options will enforce the update to keep current config and not overwrite it with the package default one.

There is no way to easily automate deployment of Oracle JRE since there is no official repository for most of the linux distros. But there’s still a workaround to automatically download the JRE and install it locally on a server by using command lines.

Here is an example of how you can download the JRE 1.8u172 from official website for a CentOS server. You’ll have to grab the URL of the package you want to download from the website http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html

First, download the package from the website by accepting the license automatically:

Then, install the package you downloaded on the server: