I know I know, there are plenty of openssl cheat sheets out there already (1 or 2). But as I keep using googling it again and again to find the most useful openssl commands I decided to do my own – the first version of the blog entries is already 3 years old actually. Another reason for creating the list is that I remember things better when I am writing the down.

The traditional way for creating a linux swapfile would be using dd to create an empty file e.g. dd if=/dev/zero of=/swapfile1 bs=1M count=2048 A faster way is to use “fallocate” e.g. (( http://www.cyberciti.biz/faq/ubuntu-linux-create-add-swap-file/ )) fallocate -l 2G /swapfile1 Don’t forget the usually procedure for swapfiles: chmod 0600 /swapfile1 chown root:root /swapfile1 mkswap /swapfile1 swapon /swapfile1 # edit /etc/fstab to add the swapfile during boot

Sometimes it’s necessary to run a complex command on a remote server witch also includes some “backticks”. Usually these commands are interpreted by the local shell so you need to use a little trick to force execution on the remote server: ssh this.is.my.beautiful.server '( echo `echo "This Command is run on the remote server" ` )' You need to use single quotes combined with brackets to use the backtick on the remote server.