Find a value and the previous timestamp

Shell Programming and Scripting
1

Hi,

I need to do a script that find a specific data in var_5 and also the previous timestamp. This is the file I have:

[2008/09/04 12:46:00]
var_1=data1
var_2=data2
var_3=data3
var_4=data4
var_5=data5
var_6=data6
var_7=data7
RESULT
PRINTOUTS:
6404
var_1=data8
var_2=data9
var_3=data10
var_4=data11
var_5=data12
var_6=data13
var_7=data14
RESULT
PRINTOUTS:
6404
var_1=data15
var_2=data16
var_3=data17
var_4=data18
var_5=data19
var_6=data20
var_7=data21
RESULT
PRINTOUTS:
6404
[2008/09/04 12:51:00]
var_1=data22
var_2=data23
var_3=data24
var_4=data25
var_5=data26
var_6=data27
var_7=data28
RESULT
PRINTOUTS:
6404
var_1=data29
var_2=data30
var_3=data31
var_4=data32
var_5=data33
var_6=data34
var_7=data35
RESULT
PRINTOUTS:
6404

What I want to do is, for exemple, find if the "data33" is in the file and if it is returns the previous timestamp, in this case "[2008/09/04 12:51:00]"

Can someone help me?

2 
awk '{
   if ($0 ~ /^\[/)
      dt = $0
   if ($0 == "var_5=data33")
      print dt
}' file
3

Thank you a lot man!! this works just like I wanted!! I don't understand what it does, if you can explain..

Anyway, once again thank you!

4

Now I need something else.. I still want the same ouput but I also want to print de var_7 value.

In the previous example, when looking for data33, should be:

[2008/09/04 12:51:00] data35

I've tried some solutions but none of them works..

Thank you

5 
awk -F\= '{
   if ($0 ~ /^\[/)
      dt = $0
   if ($0 == "var_5=data33")
      flg++
   if ($0 == "var_7=data35" && flg--)
      print dt, $2
}' file
6 
while read -r line
do
    case $line in 
        [* ) l=$line;;
        var_5*data33) echo $l;;
    esac
done < file
7

This solution has a problem because for which var_5 value I have a var_7 value and it can or can not be the same from others var_7 along the file. What I want is the var_7 value just after the specific var_5 value.

8 
awk -F\= '{
   if ($0 ~ /^\[/)
      dt = $0
   if ($0 == "var_5=data33")
      flg++
   if ($0 ~ "var_7" && flg) {
      print dt, $2
      flg = 0
   }
}' file