Nagios NRPE plugin check_file version 1.3 uses a very flexible format for specification of file age filters. Perl module Time::ParseDate is used for that purpose and following formats are supported:

 Absolute date formats:

        Dow, dd Mon yy
        Dow, dd Mon yyyy
        Dow, dd Mon
        dd Mon yy
        dd Mon yyyy
        Month day{st,nd,rd,th}, year
        Month day{st,nd,rd,th}
        Mon dd yyyy
        yyyy/mm/dd
        yyyy/mm
        mm/dd/yy
        mm/dd/yyyy
        mm/yy
        yy/mm      (only if year > 12, or > 31 if UK)
        yy/mm/dd   (only if year > 12 and day < 32, or year > 31 if UK)
        dd/mm/yy   (only if UK, or an invalid mm/dd/yy or yy/mm/dd)
        dd/mm/yyyy (only if UK, or an invalid mm/dd/yyyy)
        dd/mm      (only if UK, or an invalid mm/dd)
 

 Relative date formats:

        count "days"
        count "weeks"
        count "months"
        count "years"
        Dow "after next"
        Dow                     (requires PREFER_PAST or PREFER_FUTURE)
        "next" Dow
        "tomorrow"
        "today"
        "yesterday"
        "last" dow
        "last week"
        "now"
        "now" "+" count units
        "now" "-" count units
        "+" count units
        "-" count units
        count units "ago"

Absolute time formats:

        hh:mm:ss[.ddd]
        hh:mm
        hh:mm[AP]M
        hh[AP]M
        hhmmss[[AP]M]
        "noon"
        "midnight"

Relative time formats:

        count "minuts"
        count "seconds"
        count "hours"
        "+" count units
        "+" count
        "-" count units
        "-" count
        count units "ago"

Timezone formats:

        [+-]dddd
        GMT[+-]d+
        [+-]dddd (TZN)
        TZN

Special formats:

        [ d]d/Mon/yyyy:hh:mm:ss [[+-]dddd]
        yy/mm/dd.hh:mm