while read -r num; do ((sum += num)); done < inputfile; echo $sum

[ghostdog74s评论的后续]

bash-2.03$ uname -sr
SunOS 5.8

bash-2.03$ perl -le 'print for 1..49999998' > infile

bash-2.03$ wc -l infile
 49999998 infile

bash-2.03$  time paste -sd+ infile | bc
bundling space exceeded on line 1, teletype
Broken Pipe

real    0m0.062s
user    0m0.010s
sys     0m0.010s

bash-2.03$ time nawk '{s+=$1}END{print s}' infile
1249999925000001

real    2m0.042s
user    1m59.220s
sys     0m0.590s
bash-2.03$ time /usr/xpg4/bin/awk '{s+=$1}END{print s}' infile
1249999925000001

real    2m27.260s
user    2m26.230s
sys     0m0.660s

bash-2.03$ time perl -nle'
  $s += $_; END { print $s }
   ' infile
1.249999925e+15

real    1m34.663s
user    1m33.710s
sys     0m0.650s

下面的命令将添加所有行(awk输出的第一个字段)

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

[root@pentest3r ~]# (find / -xdev -size +1024M) | (while read a ; do aa=$(du -sh $a | cut -d "." -f1 ); o=$(( $o+$aa )); done; echo "$o";)

while read -r num; do ((sum += num)); done < inputfile; echo $sum

两行算吗?

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

然后你就可以不用多余的'cat'了:

sum < FileWithColumnOfNumbers.txt
sum   FileWithColumnOfNumbers.txt

FWIW:在MacOS X上，你可以用一行程序完成:

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