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how to add integer with expr?

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# 1  
Old 04-27-2009
how to add integer with expr?
i got a file called Marks
The format of Marks is:

12345678 5 7
23456789 7 9 3

What can i do with a loop, read expr and echo command to produce a new file like below:

12345678:12
23456789:20

and also when we adding fewer than 3 value with expr, we need to change any null value for variable to 0 so expr gets a valid argument. how can i change it?

So how can i produce a new file with the format above? Using Bourne Shel script.
Thank you for your helping!!Smilie
Last edited by mingming88; 04-27-2009 at 10:21 AM..
# 2  
Old 04-27-2009
One way in "ksh" (you don't state which shell). Note there are Posix ways of doing arithmetic in shell without using "expr" and there are ways of reading a file without using "cat". I hope I have understood the sums required because I make 7+9+3=19 .

Code:
#!/bin/ksh
typeset -i A2=0
typeset -i A3=0
typeset -i A4=0
typeset -i TOTAL=0

cat Marks | awk '{print $1,$2,$3,$4}'|while read A1 A2 A3 A4
do
        TOTAL=0
        TOTAL=`expr ${TOTAL} + ${A2}`
        TOTAL=`expr ${TOTAL} + ${A3}`
        TOTAL=`expr ${TOTAL} + ${A4}`
        echo "${A1}:${TOTAL}"
done

Last edited by methyl; 04-27-2009 at 10:31 AM.. Reason: Forgot code tags
# 3  
Old 04-27-2009
i need to use Bourne shell script.... can't use ksh
# 4  
Old 04-27-2009
Code:
nawk '{sum=0;for(i=2;i<=NF;i++) sum+=$i; print $1,sum}' OFS=: myFile

# 5  
Old 04-27-2009
Quote:
Originally Posted by methyl
One way in "ksh" (you don't state which shell). Note there are Posix ways of doing arithmetic in shell without using "expr" and there are ways of reading a file without using "cat". I hope I have understood the sums required because I make 7+9+3=19 .

#!/bin/ksh
typeset -i A2=0
typeset -i A3=0
typeset -i A4=0
typeset -i TOTAL=0

cat Marks | awk '{print $1,$2,$3,$4}'|while read A1 A2 A3 A4
do
TOTAL=0
TOTAL=`expr ${TOTAL} + ${A2}`
TOTAL=`expr ${TOTAL} + ${A3}`
TOTAL=`expr ${TOTAL} + ${A4}`
echo "${A1}:${TOTAL}"
done
Thank you for helping
# 6  
Old 04-27-2009
i need to do it with a loop, read, expr and echo command....
# 7  
Old 04-27-2009
Quote:
Originally Posted by mingming88
i need to do it with a loop, read, expr and echo command....
Could you please explain why?
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