AIX下AWK语言的操作符

awk操作符
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= += *= / = %= ^ =	赋值操作符
?		        条件表达操作符
||  &&  !		并，与，非
< <= == != >>		关系操作符
+ - * / % ^		算术操作符
+ + --			前缀和后缀
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1.设置输入域到域变量名
awk '{name=$1;color=$4; if(color ~/Yello/)print name" " is color "color}' grade.txt
P.Bunny is color Yello

2.赋值比较，通常在BEGIN部分赋值
a.在BEGIN中给变量名赋值
awk 'BEGIN {BASELINE="27   "} {if($6<BASELINE) print $0}' grade.txt
J.Lulu     06/99  48317  green    9    24   26
J.Troll    07/99  4842   Brown-3  12   26   26
b.在关系操作中使用实际数值
awk '{if($6 < 27) print $0}' grade.txt
J.Lulu     06/99  48317  green    9    24   26
J.Troll    07/99  4842   Brown-3  12   26   26

3.修改数值域取值
awk '{if($1=="M.Tansley") $5=$6-1; print $1, $6, $5, $7}' grade.txt
M.Tansley 40 39 44
J.Lulu 24 9 26
P.Bunny 35 12 28
J.Troll 26 12 26
L.Tansley 30 12 28

4.修改文本域
awk '{if($1=="J.Troll") ($1="J.Troll.L");print $1}' grade.txt
M.Tansley
J.Lulu
P.Bunny
J.Troll.L
L.Tansley

5.只显示修改记录
awk '{if( $1 == "J.Troll" ) {$1="J.Troll.L"; print $1}' grade.txt
awk: Syntax error
 at line 1 of program << {if( $1 == "J.Troll" ... >>
 context is
        {if( $1 == "J.Troll" ) {$1="J.Troll.L"; print >>>  $1} <<<
        1 extra {
awk: illegal statement
 at line 1 of program << {if( $1 == "J.Troll" ... >>
错误原因：少了一个“}”结束
awk '{if( $1 == "J.Troll" ) {$1="J.Troll.L"; print $1}}' grade.txt
J.Troll.L

6.创建新的域
awk 'BEGIN{ print "Name\t Difference"} 
{if($6 < $7) {$8=$7-$6; print $1,$8}}' grade.txt
Name     Difference
M.Tansley 4
J.Lulu 2

7.统计数据
awk '(tot += $6); END{print "Club student total points:" tot}' grade.txt
M.Tansley  05/99  48311  Green    8    40   44
J.Lulu     06/99  48317  green    9    24   26
P.Bunny    02/99  48     Yello    12   35   28
J.Troll    07/99  4842   Brown-3  12   26   26
L.Tansley  05/99  4712   Brown-2  12   30   28
Club student total points:155

8.文件长度相加
ls -l | awk ' /^[^d]/ {print $9"\t"$5} {tot += $5}
END {print "total KB:"tot}'

cat     		0
cat_file.txt    	28
data.f  		356
delete_me_and_die       284
first2  		61
grade.txt       	235
info.txt        	354
myfile  		23
test.bak        	225
test.sql        	225
who.out 		1998
wow     		229
total KB:4018
查看当前目录下的所有文件：
ls -l
total 24
-rw-r--r--   1 xxxx     group          0 Nov 19 10:12 cat
-rw-r--r--   1 xxxx     group         28 Nov 14 20:32 cat_file.txt
-rw-r--r--   1 xxxx     group        356 Nov 16 19:50 data.f
-rw-r--r--   1 xxxx     group        284 Nov 19 10:36 delete_me_and_die
-rwxr--r--   1 xxxx     group         61 Nov  8 09:15 first2
-rw-r--r--   1 xxxx     group        235 Nov 19 10:44 grade.txt
-rwxr--r--   1 xxxx     group        354 Nov 17 11:05 info.txt
-rwxr-----   1 xxxx     group         23 Nov  7 19:12 myfile
-rwxr--r--   1 xxxx     group        225 Nov 15 18:08 test.bak
-rwxr--r--   1 xxxx     group        225 Nov 15 14:12 test.sql
-rw-r--r--   1 xxxx     group       1998 Nov 15 14:15 who.out
-rw-r--r--   1 xxxx     group        229 Nov 19 14:44 wow

--the end--