Script for listing commit subjects over time period specified

what-i-did.sh

#!/bin/bash

if [[ "$@" == *'--help'* ]]; then
    echo "usage: what-i-did [since] [until] [format]"
    echo '  See `man git-log` for more information'
    echo "  Examples:"
    echo "    what-i-did              commits from self since 6am today"
    echo "    what-i-did yesterday    commits from self over last 24hrs"
    echo "    what-i-did '6am yesterday' '6pm yesterday'"
    echo "                            commits from self between 6am-6pm"
    echo "                            yesterday"
    exit 1
fi

since="${1:-6am}"
until="${2:-now}"
fmt="${3:-%s}"
author="$(git config --get user.name)"
git log --all --since="$since" --until="$until" --author="$author" --pretty=format:"$fmt"