Two ways to display elapsed time in bash

Contents

The hard way: use bash arithmetic

for N in $(seq 5) {
do
    eval "$(date +'S1=%s N1=%N')"
    echo -n "some-command: "
    some-command
    eval "$(date +'S2=%s N2=%N')"
    S1="$S1$N1"; S2="$S2$N2"; CENTI_E=$(((S2-S1+5000000)/10000000))
    # Can't use "$((CENTI_E/100)).$((CENTI_E % 100))" '102' returns '2' on
    # the '%' operation, so the result gets displayed as '1.2'
    # Also can't use '${CENTI:-2}': bash doesn't do negative starts (although
    # it can do negative lengths)
    FULL_S=$((CENTI_E/100)); L=${#FULL_S}
    echo "$FULL_S.${CENTI_E:$L} seconds"
done

The easy way: use TIMEFORMAT

TIMEFORMAT="%2R seconds"
echo -n "some-command: "
time some-command



About

Ramblings about Linux and other things

Archives

Tags