while :; do date; awk '{printf "1 minute load: %.2f\n", $1; printf "5 minute load: %.2f\n", $2; printf "15 minute load: %.2f\n", $3}' /proc/loadavg; sleep 3; done
while :; do ...; done is an infinite loop. You can interrupt it with Control-c.
The file /proc/loadavg contains a line like this:
0.01 0.04 0.07 1/917 25383
Where the first 3 columns represent the 1, 5, 15 minute loads, respectively.
In the infinite loop we print the current date, then the load values nicely formatted (ignore the other values), then sleep for 3 seconds, and start again.
/proc/loadavg is only available in Linux.
while [ 1 == 1 ]; do cat /proc/loadavg | awk '{printf "1 minute load: %.2f\n", $(NF-5)}' && cat /proc/loadavg |awk '{printf "5 minute load: %.2f\n", $(NF-3)}' && cat /proc/loadavg |awk '{printf "15 minute load: %.2f\n", $(NF-2)}'; sleep 3; date; done