How to log timestamp before every line in log? [closed] - linux

Question

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack Exchange site, you can leave a comment to explain where the question may be able to be answered.
Closed 3 years ago.
Improve this question
I want to log memory usage every 5th second and hence I am using free -s 5 -m> memory.log
How to add timestamp before every lie in this log?
Expected output:
Tue Jan 21 06:50:44 UTC 2020
total used free shared buffers cached
Mem: 7809 6268 1540 0 57 3497
-/+ buffers/cache: 2713 5095
Swap: 0 0 0
Tue Jan 21 06:50:49 UTC 2020
total used free shared buffers cached
Mem: 7809 6268 1540 0 57 3497
-/+ buffers/cache: 2713 5095
Swap: 0 0 0

Answer 1

I found out that there is no single line command to do that and this can be achieved by writing and executing a script.
So the shell script is:
#!/bin/bash -e
echo " date time $(free -m | grep total | sed -E 's/^ (.*)/\1/g')" >> /var/log/memory_utilisation.log
while true; do
echo "$(date '+%Y-%m-%d %H:%M:%S') $(free -m | grep Mem: | sed 's/Mem://g')" >> /var/log/memory_utilisation.log
sleep 5
done