Bash command to sum a column of numbers

The following command will add all the lines(first field of the awk output)

awk '{s+=$1} END {print s}' filename

Does two lines count?

awk '{ sum += $1; }
     END { print sum; }' "$@"

You can then use it without the superfluous 'cat':

sum < FileWithColumnOfNumbers.txt
sum   FileWithColumnOfNumbers.txt

FWIW: on MacOS X, you can do it with a one-liner:

awk '{ sum += $1; } END { print sum; }' "$@"

I like the chosen answer. However, it tends to be slower than awk since 2 tools are needed to do the job.

$ wc -l file
49999998 file

$ time paste -sd+ file | bc
1448700364

real    1m36.960s
user    1m24.515s
sys     0m1.772s

$ time awk '{s+=$1}END{print s}' file
1448700364

real    0m45.476s
user    0m40.756s
sys     0m0.287s

Using existing file:

paste -sd+ infile | bc

Using stdin:

<cmd> | paste -sd+ | bc

Edit: With some paste implementations you need to be more explicit when reading from stdin:

<cmd> | paste -sd+ - | bc

Options used:

-s (serial) - merges all the lines into a single line

-d - use a non-default delimiter (the character + in this case)