Category: Linux

Determine which processes are using swap in Linux

Some servers may have several applications, each running in their own allocated piece of RAM and SWAP.  It seems easy enough to use `top` to determine memory usage, but it wasn't so obvious (to me) as to how to determine swap usage.  A nifty little command called smem to the rescue. So what is smem?  It is a "Report memory...Read More »

ssh logins using keys

I have wanted to experiment and expand upon different ways of ssh'ing into one linux box from another using the ssh-keygen.  This article demonstrates several different methods that I have tested and used throughout the years. Actually what has happened, is that over time, scripting evolved and always seem to make tweaks along the way. Another variation. A more lengthy...Read More »

Spacewalk Certificate expiration warning [Resolved] 2018

I'm not going to go into detail as to what spacewalk is and what this message is all about, you are here for a reason.  You may have received an auto-generated email from Spacewalk to "inform you that your Spacewalk Certificate has expired on your [fqdn] server. After 4 day(s) the systems management services provided by your Spacewalk Server will...Read More »

How to add desktop icons on CentOS 7

For the most part, I prefer to work using the terminal on a minimal install of Linux; however, there are those occasional times where the GUI is necessary.  Recently faced with having to add a few desktop shortcuts to the Desktop posed a bit of a problem for me. Basically, wanted to achieve two things, a Desktop icon to launch...Read More »

VIM: Join Lines

I had a document where I wanted to join every other line.  I tried several approaches on a Windows box using Cygwin but only one worked with a couple variations.  Using the vim editor.  This is a new trick to me, and wanted to jot it down before I forget about. The file looked something like this. One approach was...Read More »

Linux: How to logout a user

A user was logged in via XRDP and the screen locked.  Each attempt to logon also resulted in a locked screen.  Rebooting is not an option.  There needed to be a way to identify the user and forcibly log them off, and there is. Logged on as root and typing the who command lists users and logons.  A great working...Read More »

Apache httpd log rotation does not compress the logs

A CentOS 7 installation with a simple yum install of httpd also creates a logrotation script.  The script does log rotate files, however, there is no compression.  A quick look at the script indicates that some compression settings are put into place, but as experience indicates, not enough to do the job. By default, this is the logoration script as...Read More »