Compare different grep-like methods

grep-comparison.sh

#!/bin/bash
if ! which python3 >/dev/null 2>&1; then
    echo 'python3 required'
fi
if [ -z "$1" ]; then
    echo "greptest.sh <regex|string>"; exit 1
fi
mytime () {
    start=`date +%s.%N`
    $@ >/dev/null 2>&1
    end=`date +%s.%N`
    echo $(calc "$end - $start")
}
calc () {
    python3 -c "print($1)"
}
get_time () {
    out=$(mytime $@)
    printf "%s\n" $out
}

test_cmd() {
    limit=$1; total=0.0
    for i in $(seq 1 $limit); do
        val=$(get_time "${@:2}" "${string}")
        total=$(calc "$total + $val")
    done
    echo $(calc "$total / $limit")
}

string=$1
rounds=100
printf 'grep: %s\n' $(test_cmd $rounds grep -r -E)
printf 'git grep: %s\n' $(test_cmd $rounds git grep -E)
printf 'rg: %s\n' $(test_cmd $rounds rg)
printf 'ack: %s\n' $(test_cmd $rounds ack)
printf 'ag: %s\n' $(test_cmd $rounds ag)