awk 列相加求和

[linux]$ cat test.txt

123.52
125.54
126.36

[linux]$ awk '{sum += $1};END {print sum}'  test.txt

375.42

对文件test中 第一列为aaa的行求和

[linux]$  cat test.txt
aaa 123.52
bbb 125.54
aaa 123.52
aaa 123.52
ccc 126.36

[linux]$ awk '/aaa/ {sum += $2};END {print sum}' test.txt

370.56