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Variable Initialize


 
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# 1  
Old 08-07-2005
Variable Initialize

Hi, i m trying to loop a variable value, Basically i m reading variable value from an input file and using in rest of the program. Bu my problem is when i first time read value and assign to variable it works fine, but in second read it concatinate second value to first value with a LF. I want to use one value at a time. Here is what i am doing

carrier_id=`cat ${cnt_path}mpd_rxsh_carrier_id.dat | head -${i}`
Value::
1st read
253090
2nd read
253090
253029
3rd read
253090
253029
255055

my input file mpd_rxsh_carrier_id.dat is like
253090
253029
255055

Please let me know how i can initialize a variable to hold only new value or there is any other way to do this.

thanks
# 2  
Old 08-07-2005
Quote:
Originally Posted by coolbudy
Hi, i m trying to loop a variable value, Basically i m reading variable value from an input file and using in rest of the program. Bu my problem is when i first time read value and assign to variable it works fine, but in second read it concatinate second value to first value with a LF. I want to use one value at a time. Here is what i am doing

carrier_id=`cat ${cnt_path}mpd_rxsh_carrier_id.dat | head -${i}`
Value::
1st read
253090
2nd read
253090
253029
3rd read
253090
253029
255055
Your error is quite obvious. Your loop variable is 'i', and as the value of i increases, head -${i} returns more and more lines. Let me explain.

At your first pass through the loop, the value of i is 1. You get the first line. So far so good. At the second pass the value of i becomes 2 and head -${i} becomes head -2, which returns the first two lines.. this will continue as long as the value of i increases.

If you want to read the value of carrier id from the file into variable carrier_id, you have to use
Code:
while read carrier_id;do
..
# do your stuff here
..
done < ${cnt_path}mpd_rxsh_carrier_id.dat

# 3  
Old 08-07-2005
Thanks Buddy...It works...After posting my query i realize tht head is not meant for it...

Thanks for giving the best solution.

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