Prints a reminder if you haven't fetched from a git repo for some period of time

git-fetch-reminder.sh

#!/bin/bash
#
# Print a reminder if a fetch has not been done in n hours.
#
# There are multiple ways you could invoke this; for example, to have it run
# whenever you change directory you could do:
#
# cd() { command cd "$@"; ~/bin/git-fetch-reminder.sh 2>/dev/null; }
#

declare -r fetch_threshold_hours=6

main() {
    local fetch_head
    local repo_root
    local verbose=false

    if [ "${1:-}" == "-v" ]; then
        verbose=true
    fi

    repo_root=$(git rev-parse --show-toplevel 2> /dev/null)
    if [ -z "$repo_root" ]; then
        echo "ERROR: Not in a repo" >&2
        return 1
    fi

    fetch_head="${repo_root}/.git/FETCH_HEAD"
    if [ -z "fetch_head" ]; then
        echo "${fetch_head} is missing. You may want to do a \`git fetch\`."
        return 0
    fi

    local last_fetch
    local last_fetch_readable
    local fetch_threshold

    case $OSTYPE in
    darwin*)
        last_fetch="$(stat -f '%m' $fetch_head)"
        last_fetch_readable="$(date -r ${last_fetch})"
        fetch_threshold="$(date -v-${fetch_threshold_hours}H +%s)"
    ;;
    *)
        last_fetch="$(stat -c %Y $fetch_head)"
        last_fetch_readable="$(date -d ${last_fetch})"
        fetch_threshold="$(date -d'${fetch_threshold_hours} hours ago' +%s)"
    ;;
    esac

    if $verbose; then
        echo "Info: Last fetch: ${last_fetch_readable}"
    fi

    if [ $last_fetch -lt $fetch_threshold ]; then
        echo "Warning: Last fetch was at ${last_fetch_readable}; you may want to do a \`git fetch\`."
    fi
}

# Run main if not being sourced
if [ "$0" == "$BASH_SOURCE" ]; then
    main "$@"
fi