#!/bin/sh
set -o pipefail
: "${CACHE_AGE:=300}"
test -n "$CACHE_DIR" || exit 1
cache="$CACHE_DIR/$(echo "$*" | base64)"
if test -f "$cache"; then
    now="$(date +%s)"
    mod="$(stat -c %Y "$cache")"
    if test $((mod + CACHE_AGE)) -gt "$now"; then
        if ! test -s "$cache"; then
            exit 1
        fi
        exec cat "$cache"
    fi
fi
"$@" | tee "$cache"