awk控制函数

$ cat datafile
northwest  NW  Joel Craig     3.0   .98   3    4
western    WE  Sharon Kelly   5.3   .97   5    23
southwest  SW  Chris Foster   2.7   .8    2    18
southern   SO  May Chin       5.1   .95   4    15
southeast  SE  Derek Johnson  4.0   .7    4    17
eastern    EA  Suan Beal      4.4   .84   5    20
northeast  NE  TJ Nichols     5.1   .94   3    13
north      NO  Val Shultz     4.5   .89   5    9
central    CT  Sheri Watson   5.7   .94   5    13

$ awk ‘{if($5 >= 4.5) next; print $1}‘ datafile
northwest
southwest
southeast
eastern
north

$ awk ‘{if($2 ~ /S/){print ;exit 0}}‘ datafile
southwest  SW  Chris Foster   2.7   .8    2    18

$ echo $?
0