I had a case where I had a pool of servers. And I wanted email notifications if any server or some of them meet the condition. The condition was if my rsync exceeds X number of files, send me a mail. The problem came in the moment when only 1 server met the condition but I received mails for all of them. It was annoying, spamming and WRONG.
The example I am going to show you does NOT include the rsync part because it is simply useless but you will see simulation with a predefined value.
pool=”s1 s2 s3″
for HOST in $pool; do
if [[ $number -eq 5 || $1 == true ]];then
echo “No mail”
echo “Test $emptyvar $HOST” | mutt -s “Test” email@example.com
echo “continue to actual”
Really quick bro tip how to assign a user to have permissions over a single directory without adding him/her on a group or change directory ownership. Simply use setfacl:
setfacl -m u:username:rwx myfolder
I want to start off by saying that this is my very first time writing an article of any sort. Thanks to Rosen for letting me write as a guest on his awesome website. Anyhow, I hope you find the information below useful and practical as much as I have. Enjoy!
Several months ago, I quit Tech Support and started working as a Sys Admin for a storage company (still learning, there’s a looong way to go…). I knew about the power of SSH before, but on several occasions, I found out that creating SSH tunnels can be super useful and it gives you the freedom to quickly access devices from anywhere you want.
In my particular situation, I have a Raspberry Pi 3 sitting at home, up and running all the time, which I use for pretty much anything that I want to experiment with, whenever I get the chance… That last part is key: I want to be able to access the little gadget whenever I feel like it, and not be restricted by my location or the computer I’m accessing it from.
After I set up proper port forwarding in my home router (check the web if you don’t know how to do that yet, it’s very useful), I had to SSH to my external IP address and the specific port, which would in turn forward that to port 22 on my Raspberry Pi, allowing me to type my password at the prompt. Pretty basic procedure but I wasn’t really happy with the fact that I have to specify and address, a port, and type a password. I wanted to create some sort of an alias which would include all that information. I wanted the process to be as automated as possible, and after quite some time digging around on the web, here are the possible solutions that I found:
Simple SSH with an SSH key
You can always use sshpass and use the -p flag to give the password in the command itself, but this is not very safe, as anybody with access can check the CLI history or the current SSH session process (ps aux | grep ssh) and see the password.
Continue reading “How to create ssh tunnels and access locally any remotely hosted services”
I was extremely tired of typing hostnames of the machines we are using at the office. I had these days when I ssh to a single machine 20 times. And I don’t want to remember names or IPs. Of course, you can generate private keys and passphrase but if you don’t have this option or knowledge, you can make SSH alias to a common server. Follow few easy steps:
Use you favorite text editor, I like MC:
In the config file add these lines (and put your server settings):
By typing in the terminal “ssh ALIAS_NAME” this will lead you to the password prompt of the server instantly.