Help with code

Shell Programming and Scripting
1

Dear Gurus , kindly take a look at this code

#!/bin/bash
declare -i total=0
declare -i frst=0
hr=`cat test2 | head -1 | cut -b12-13`
#echo $hr
for name in `cat test2`
do
hour=`echo $name | cut -b12-13`
#echo $hour
if [$hour == $hr]
then
#echo $name
frst=`echo $name | cut -f 4 -d ,`
total=`expr $total+$frst`
else
echo $total
declare -i total=0
declare -i frst=0
frst=`echo $name | cut -f 4 -d ,`
total=`expr $total+$frst`
fi
done

Algo ang logic seems to be correct , hr and hour are two strings and i m comparing them as you can see , but its not working somehow
second decalartion of total and frst is just to set them to zero again

Regards

2

Why? You are assigning them immediately afterwards....

3

The if statement syntax is wrong. Also, perhaps use bash for integer arithmetic instead of expr. Check the bash man pages for details of both.

4

What is the logic behind the script? The statements seems to repeat in the if loop. And i think there is no reason for the if loop since the operations are same in the then clause and the else clause.

Provide us more details

5

Well
here is the text of test2

2007-05-31-0000,0,0,537,538,489,490,0,0,0,0,0,0,46,46
2007-05-31-0001,0,0,552,552,489,489,2,2,0,0,0,0,60,60
2007-05-31-0002,0,0,526,526,482,482,0,0,0,0,0,0,43,43
2007-05-31-0003,1,1,575,575,518,518,0,0,0,0,0,0,57,56
2007-05-31-0004,0,0,522,522,480,480,0,0,0,0,0,0,42,42
2007-05-31-0005,0,0,533,533,479,479,0,0,0,0,0,0,53,53
2007-05-31-0006,0,0,489,489,442,442,0,0,0,0,0,0,47,47
2007-05-31-0007,0,0,504,504,473,473,0,0,0,0,0,0,31,31
2007-05-31-0008,0,0,485,484,451,451,0,0,0,0,0,0,34,33
2007-05-31-0009,0,0,475,475,442,442,0,0,0,0,0,0,33,33
2007-05-31-0010,0,0,506,507,461,461,0,0,0,0,0,0,45,46
2007-05-31-0011,0,0,485,484,450,450,0,0,0,0,0,0,35,34
2007-05-31-0012,0,0,485,486,434,434,0,0,0,0,0,0,51,52
2007-05-31-0013,0,0,447,446,411,410,1,1,0,0,0,0,35,35
2007-05-31-0014,0,0,471,472,423,424,1,1,0,0,0,0,46,46
2007-05-31-0015,0,0,445,445,398,398,0,0,0,0,0,0,47,47
.............
..............

well 2007-05-31-0015 is the date followed by time , as you can see it is updated every minute , so what i m trying to do is to sum fourth "," separated field ( italics ) for each , hour based on this algo
what algo is doing is summing all the values untill second character of time changes ( bold )
Problem is definitely in if statement , as i m comparing contents of two string variables , declaration of total and frst is just to flush their contents and set them back to zero
i hope its been clear now

Regards

6

Try and adapt the following script :

#!/usr/bin/bash
# Script File : test2.sh
# Input  File : test2.txt

declare -i total frst
while IFS=, read timestamp f2 f3 frst rest
do
   hour=${timestamp:11:2}
   : ${prv_hour:=$hour}
   if [ $hour != ${prv_hour} ]
   then
      echo "$hour => $total"
      (( total = 0 ))
      prv_hour=$hour
      hour=
   fi
   (( total += frst ))
done < test2.txt
[ -n "$hour" ] && echo "$hour => $total"

Input File:

$ cat test2.txt
2007-05-31-0000,0,0,537,538,489,490,0,0,0,0,0,0,46,46
2007-05-31-0001,0,0,552,552,489,489,2,2,0,0,0,0,60,60
2007-05-31-0002,0,0,526,526,482,482,0,0,0,0,0,0,43,43
2007-05-31-0003,1,1,575,575,518,518,0,0,0,0,0,0,57,56
2007-05-31-0004,0,0,522,522,480,480,0,0,0,0,0,0,42,42
2007-05-31-0005,0,0,533,533,479,479,0,0,0,0,0,0,53,53
2007-05-31-0006,0,0,489,489,442,442,0,0,0,0,0,0,47,47
2007-05-31-0007,0,0,504,504,473,473,0,0,0,0,0,0,31,31
2007-05-31-0008,0,0,485,484,451,451,0,0,0,0,0,0,34,33
2007-05-31-0009,0,0,475,475,442,442,0,0,0,0,0,0,33,33
2007-05-31-0010,0,0,506,507,461,461,0,0,0,0,0,0,45,46
2007-05-31-0011,0,0,485,484,450,450,0,0,0,0,0,0,35,34
2007-05-31-0012,0,0,485,486,434,434,0,0,0,0,0,0,51,52
2007-05-31-0013,0,0,447,446,411,410,1,1,0,0,0,0,35,35
2007-05-31-0014,0,0,471,472,423,424,1,1,0,0,0,0,46,46
2007-05-31-0015,0,0,445,445,398,398,0,0,0,0,0,0,47,47
2007-05-31-0100,0,0,537,538,489,490,0,0,0,0,0,0,46,46
2007-05-31-0101,0,0,552,552,489,489,2,2,0,0,0,0,60,60
2007-05-31-0102,0,0,526,526,482,482,0,0,0,0,0,0,43,43

Execution :

$ test2.sh
01 => 8037
01 => 1615
$

Jean-Pierre.

7 
#!/bin/bash
declare -i total=0
declare -i frst=0
hr=`cat test2 | head -1 | cut -b12-13`
for name in `cat test2`
do
        hour=`echo $name | cut -b12-13`
        if [ "$hour" = "$hr" ]
        then
                frst=`echo $name | cut -f 4 -d ,`
                total=`expr $total+$frst`
        else
                echo "The sum of $hr hour = $total"
                declare -i total=0
                declare -i frst=0
                frst=`echo $name | cut -f4 -d,`
                total=`expr $total+$frst`
        fi
        hr=$hour
done
echo "The sum of $hour hour = $total"

Input file : test2

2007-05-31-0000,0,0,537,538,489,490,0,0,0,0,0,0,46,46
2007-05-31-0001,0,0,552,552,489,489,2,2,0,0,0,0,60,60
2007-05-31-0002,0,0,526,526,482,482,0,0,0,0,0,0,43,43
2007-05-31-0003,1,1,575,575,518,518,0,0,0,0,0,0,57,56
2007-05-31-0004,0,0,522,522,480,480,0,0,0,0,0,0,42,42
2007-05-31-0005,0,0,533,533,479,479,0,0,0,0,0,0,53,53
2007-05-31-0006,0,0,489,489,442,442,0,0,0,0,0,0,47,47
2007-05-31-0007,0,0,504,504,473,473,0,0,0,0,0,0,31,31
2007-05-31-0008,0,0,485,484,451,451,0,0,0,0,0,0,34,33
2007-05-31-0009,0,0,475,475,442,442,0,0,0,0,0,0,33,33
2007-05-31-0010,0,0,506,507,461,461,0,0,0,0,0,0,45,46
2007-05-31-0011,0,0,485,484,450,450,0,0,0,0,0,0,35,34
2007-05-31-0012,0,0,485,486,434,434,0,0,0,0,0,0,51,52
2007-05-31-0113,0,0,447,446,411,410,1,1,0,0,0,0,35,35
2007-05-31-0114,0,0,471,472,423,424,1,1,0,0,0,0,46,46
2007-05-31-0215,0,0,445,445,398,398,0,0,0,0,0,0,47,47

Output

$ ./test.sh
The sum of 00 hour = 6674
The sum of 01 hour = 918
The sum of 02 hour = 445