Using shuf to select random ports in a cluster

I found this Stack OverFlow answer about generating random numbers with a bash command and I’ve been using it to randomly select ports in a cluster.

It uses the shuf command (typing man shuf opens the manual on linux)

curl http://127.0.0.1:$(shuf -i 4000-4007 -n1)

I was reading the man pages and I found that you can do so much more with this simple command, a few cool examples are:

• Randomize lines in a file (this is useful if I have a list of file names of training data and I want to do a quick train_test_split)

shuf files.txt

• Pick seven random numbers out of an input range

seq 1 10010 | shuf -n 7

• And finally, the last one doesn’t really need shuf but I found it while I was exploring, so I’m just putting it here. This one is the coolest, you can generate random passwords by taking random bytes from /dev/urandom, filter for alphanumeric characters, and choose how many ever characters you want. I am definitely using this the next time my institute bugs me about changing my email passwords.

head /dev/urandom | tr -dc A-Za-z0-9 | head -c 9 | shuf -n 1