A shell script for monitoring memory usage

I guess many people wrote this kind of scripts already. But sometimes searching is more complicated than just writing a new one. 😅 If you know a keyword, please tell me.

This script should work with other commands. I use target/release/main because I want to test my program built from Rust's Cargo. I suppose other commands can replace target/release/main.

$CMD > log 2>&1 &                                                                                                                                                           
export PID=$!                                                                                                                                                               
echo "Process $PID is running ..."                                                                                                                                          
trap "echo kill $PID; kill $PID; exit" INT QUIT                                                                                                                             
rm -f mem.tsv                                                                                                                                                               
while true                                                                                                                                                                  
    tm=`date '+%Y-%m-%dT%H:%M:%S'`                                                                                                                                          
    rss=`ps -u | awk -v PID=$PID '{ if ($2 == PID) { print $6; } }'`                                                                                                        
    echo "$tm\t$rss" >> mem.tsv                                                                                                                                             
    sleep 10                                                                                                                                                                

It logs memory usage in mem.tsv, so I should be able to plot a graph by LibreOffice Calc easily.