execute shell script program

Question

echo Enter 2 values: 
read val1 val2
c = `expr $val1 + $val2`
echo $c

While executing the shell script, I am getting the following problem:

addition.sh: 3: addition.sh: c: not found

Please help!!

Use c=$(( val1 + val2)) instead of c=$(expr $val1 + $val2; the expr command is (mostly) obsolete in modern shells. — chepner
– chepner, Commented Jan 28, 2014 at 17:56

Beano · Accepted Answer · 2014-01-28 16:16:24Z

4

This is because you put whitespace between the variable 'c' and the '='. Hence, the shell assumes c is a command and =, and expr $val1 + $val2 are parameters given:

So instead of

c = `expr $val1 + $val2`
 ^ ^

write

c=$(expr $val1 + $val2)

All together:

echo Enter 2 values: 
read val1 val2
c=$(expr $val1 + $val2)
echo $c

Note that you can also get the result of the sum with:

echo $(( val1 + val2 ))

As a general rule, use var=$(command) to save a command output in a variable.

edited Jan 28, 2014 at 16:16

Beano

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answered Jan 28, 2014 at 15:25

fedorqui

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