Bleach has a shelf life of 6 to 12 months.

After one year the sodium hypochlorite will have broken down into salt and water, which will not be helpful in your battle against the Black Death. According to the University of Nebraska’s guidelines on chemical disinfectants for biohazardous materials, “bleach loses 20-50% of its sodium hypochlorite concentration after 6 months”.

Bottles of Clorox bleach are stamped with a date code which when properly decoded will indicate the date of manufacture. The first 7 characters in the label on one of my bottles are A819275, indicating that it was manufactured in plant A8 on the 275th day of 2019, or October 2nd. The previously mentioned dateutils proves its usefulness here.

$ datediff 2019-275 now
169
$ datediff 2019-275 now -f "%m months, %d days"
5 months, 17 days

A simple shell function may be used to decode the date.

jul () {
    date -d "$1-01-01 +$2 days -1 day" "+%Y-%m-%d";
}

$ jul 2019 275
2019-10-02