How to overwrite multiple outputted lines from a bash script into the terminal

Question

I have a kubernetes command kubectl get pods which prints to the terminal this output

 NAME READY STATUS RESTARTS AGE redis-cart-74594bd569-ffrhk 1/1 Running 0 40m

I want this command to run repeatedly every two seconds in a bash script. However, I want the output to overwrite the last input.

Currently, I can get it to overwrite one line (the first outputted line) by using a carriage return. But it doesn't overwrite the second line.

How can I overwrite previously outputted text from my bash script?

By script looks like this atm

#!/bin/bash variable=$(kubectl get pods) while true do variable=$(kubectl get pods) echo -ne "$variable" "\r" sleep 2 done exit

I don't understand why you want to do that if you have available commands such us watch. — vsergi
– vsergi, Commented Oct 12, 2021 at 10:39
I didn't realise the watch commands existence, looking into it now — testing495
– testing495, Commented Oct 12, 2021 at 10:41

Boris · Accepted Answer · 2021-10-12 10:44:42Z

Add clear command to the loop:

#!/bin/bash variable=$(kubectl get pods) while true do variable=$(kubectl get pods) clear echo -ne "$variable" "\r" sleep 2 done

But, you can use watch or -w to get a similar result without a special script.

Mario · Accepted Answer · 2021-10-12 10:45:06Z

try watchto refresh output ...

watch kubectl get pods

To end the process you can use CTRL+C or look for the process via ps or pgrepand send a SIGINT like pgrep watch kubectl | xargs kill -1.

2 Answers 2