Question: Reading the Output of Top

[Tony Baechler]

On 5/7/2016 4:24 AM, Parham Doustdar wrote:
> Top is unusable without such a feature, but you and other people replying to
> this thread seem to be using it just fine. So, what tricks do people use in
> order to memorize what column is for what value? I have this problem when
> reading the output of commands like |free -m|, too.


Well, I just listen very carefully. I've not had a problem with it, but I 
see what you mean with top in particular. It's hard to know what's going on 
when you hear a bunch of numbers scrolling past. That's why I suggested 
parking the cursor, but that doesn't stop the output. I would suggest "top 
-n1" to only show the information once or increase the refresh rate as John 
suggests.

Regarding free memory, I cheat. You can actually do this with top and most 
other commands. In Linux, there is a special filesystem called /proc. It's 
worth exploring some time as you can learn lots of useful information. All 
top, ps, free and lots of other commands do is reformat the output of files 
under /proc to make them look nicer. I don't know what files top uses, but 
read the man page. For fun, try the following two commands and let us know 
what you think:

cat /proc/meminfo
less /proc/cpuinfo

You can do the same with the ps command. All ps does on Linux is go through 
/proc and print out the process names, memory and CPU usage, etc. I find ps 
more useful and easier though, especially when there are hundreds of running 
processes on most servers.