how to add two numbers together using bash

Question

I have the following file:

lab1:/etc/scripts# cat /tmp/tmp.PGikhA/audit.txt                                
   344 server1                                                                            
     1 server2

I want to be able to add the numbers from each row together - so in this case, I want to add 344 + 1 and end up with 345.

So far, I have the following steps figured out:

lab-1:/etc/scripts# cat /tmp/tmp.PGikhA/audit.txt |awk '{print $1}'              
344                                                                                                    
1                     

But I don't know how to add them together. I know that I can just use $a + $b syntax, but how do I get the 344 and 1 into separate variables to do that?

Thanks.

EDIT 1

I'm getting two values returned instead of just the one total. Can't see what I'm doing wrong:

lab-1:/etc/scripts# cat /tmp/tmp.jcbiih/audit.txt | awk '{print $1}' | awk '{ sum+=$1} {print      
sum}'                                                                                                                    
344                                                                                                                      
345                                                                                                                      
lab-1:/etc/scripts# cat /tmp/tmp.jcbiih/audit.txt  | awk '{ sum+=$1} {print sum}'                  
344                                                                                                                      
345                                                                                                                      

Answer 1

You can do your math in awk easily. Here is an example:

awk '{ total+=$1 } END { print total }'

If you really wanted to use bash, you could use a simple loop to read one line at a time and add it up:

count=0 
while read -r number _; do # put the first column in "number" and discard the rest of the line
    count=$(( count + number )) 
done < /tmp/foo
echo $count