# достаём день, год, и старый месяц
day=`date '+%d'`
year=`date '+%Y'`
old_month=`date -v-1m '+%m'`
# Если первое число месяца, и предыдущий месяц
# был  12  - то вычисляем старый год
# если первое число выполняем содержимое:
if [ ${day} =  01  ]
then
        if [ ${old_month} =  12  ]
            then
                old_year=`date -v-1Y '+%Y'`
            else
                old_year=${year}
        fi
# считаем SARG`ом статистику по http
#################  SARG #########################
/usr/local/bin/sarg -l /var/old_log/${old_year}/${old_month}/squid.log

old_month=`date -v-1m '+%m'`

     -v      Adjust (i.e., take the current date and display the result 
of the
             adjustment; not actually set the date) the second, minute, 
hour,
             month day, week day, month or year according to val.  If val is
             preceded with a plus or minus sign, the date is adjusted 
forwards
             or backwards according to the remaining string, otherwise the
             relevant part of the date is set.  The date can be adjusted as
             many times as required using these flags.  Flags are processed 
in
             the order given.

             When setting values (rather than adjusting them), seconds are 
in
             the range  0 - 59 , minutes are in the range  0 - 59 , hours are in the
             range  0 - 23 , month days are in the range  1 - 31 , week days are in
             the range  0 - 6  (Sun-Sat), months are in the range  1 - 12  (Jan-Dec)
             and years are in the range  80 - 38  or  1980 - 2038 .

             If val is numeric, one of either y, m, w, d, H, M or S must be
             used to specify which part of the date is to be adjusted.

             The week day or month may be specified using a name rather than 
a
             number.  If a name is used with the plus (or minus) sign, the
             date will be put forwards (or backwards) to the next (previous)
             date that matches the given week day or month.  This will not
             adjust the date, if the given week day or month is the same as
             the current one.

             When a date is adjusted to a specific value or in units greater
             than hours, daylight savings time considerations are ignored.
             Adjustments in units of hours or less honor daylight saving 
time.
             So, assuming the current date is March  26 ,  0 : 30  and that the 
DST
             adjustment means that the clock goes forward at  01 : 00  to  02 : 00 ,
             using -v +1H will adjust the date to March  26 ,  2 : 30 .  Likewise,
             if the date is October  29 ,  0 : 30  and the DST adjustment means 
that
             the clock goes back at  02 : 00  to  01 : 00 , using -v +3H will be 
nec-
             essary to reach October  29 ,  2 : 30 .

             When the date is adjusted to a specific value that doesn't 
actu-
             ally exist (for example March  26 ,  1 : 30  BST  2000  in the
             Europe/London timezone), the date will be silently adjusted 
for-
             wards in units of one hour until it reaches a valid time.  When
             the date is adjusted to a specific value that occurs twice (for
             example October  29 ,  1 : 30   2000 ), the resulting timezone will be
             set so that the date matches the earlier of the two times.

             Adjusting the date by months is inherently ambiguous because a
             month is a unit of variable length depending on the current 
date.
             This kind of date adjustment is applied in the most intuitive
             way.  First of all, date tries to preserve the day of the 
month.
             If it is impossible because the target month is shorter than 
the
             present one, the last day of the target month will be the 
result.
             For example, using -v +1m on May  31  will adjust the date to 
June
              30 , while using the same option on January  30  will result in 
the
             date adjusted to the last day of February.  This approach is 
also
             believed to make the most sense for shell scripting.  Neverthe-
             less, be aware that going forth and back by the same number of
             months may take you to a different date.

             Refer to the examples below for further details.