Question

I have text file with entries like
123
112
3333
44
2

How to add these numbers and get the sum of these.

Answer 1

Example:

$ cat numbers.txt
123 112 3333 44 2

$ SUM=0; for i in `cat numbers.txt`; do SUM=$(($SUM + $i)); done; echo $SUM
3614

See also: Bash Programming Introduction, section on arithmetic evaluation

Another way would be to use bc, an arbitrary precision calculator language:

$ echo '123 112 3333 44 2' | tr ' ' '\n' | paste -sd+ | bc
3614

Paste usually works on lines, so we need tr.