$ netstat|head -5|awk '{print $1, $4}'
Active (w/o
Proto Local
tcp amd10:34315
tcp amd10:49829
tcp amd10:47962
$ echo "bbbb ccc"| awk '{print $1}'
$ cat a.dat|awk '{print $1, $4}'
$ awk '{print $1, $4}' a.dat $ netstat|head -5|awk '{printf "%-8s %-8s %-8s %-12s %-22s %-10s\n",$1,$2,$3,$4,$5,$6}'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign
tcp 0 0 amd10:45977 amd200:ssh TIME_WAIT
tcp 0 0 amd10:54689 amd40:ssh TIME_WAIT
tcp 0 0 amd10:54688 amd40:ssh TIME_WAIT | 变量 | 含义 |
|---|---|
| $0 | 当前记录（这个变量中存放着整个行的内容） |
| $1~$n | 当前记录的第n个字段，字段间由FS分隔 |
| FS | 输入字段分隔符 默认是空格或Tab |
| NF | 当前记录中的字段个数，就是有多少列 |
| NR | 已经读出的记录数，就是行号，从1开始，如果有多个文件话，这个值也是不断累加中。 |
| FNR | 当前记录数，与NR不同的是，这个值会是各个文件自己的行号 |
| RS | 输入的记录分隔符， 默认为换行符 |
| OFS | 输出字段分隔符， 默认也是空格 |
| ORS | 输出的记录分隔符，默认为换行符 |
| FILENAME | 当前输入文件的名字 |
$ awk 'BEGIN{FS=":"} {print $1,$3,$6}' /etc/passwd |tail -2
chenn 624 /home/chenn
yanm 625 /home/yanm
$ awk -F : '{print $1,$3,$6}' /etc/passwd |tail -2
$ awk -F [:/] '{print $1,$3,$6}' /etc/passwd |tail -2
$ awk -F : '{print $1,$3,$6}' OFS="\t" /etc/passwd| tail -2
chenn 624 /home/chenn
yanm 625 /home/yanm$ netstat|head -5|awk '($3==0 && $6=="TIME_WAIT")'
tcp 0 0 amd10:53270 amd40:ssh TIME_WAIT
tcp 0 0 amd10:53271 amd40:ssh TIME_WAIT
tcp 0 0 amd10:53272 amd40:ssh TIME_WAIT
$ netstat|head -5|awk '($3==0 && $6=="TIME_WAIT")||NR==1'
Active Internet connections (w/o servers)
tcp 0 0 amd10:53666 amd36:ssh TIME_WAIT
tcp 0 0 amd10:55245 amd30:ssh TIME_WAIT
tcp 0 0 amd10:58951 amd200:ssh TIME_WAIT
$ netstat|head -5|awk 'NF==6'
$ netstat|head -70|awk '($2>0)'
$ netstat|head -5|awk '($3==0 && $NF=="TIME_WAIT"){print $1} '
$ netstat|head -5|awk '($3==0 && $6 ~/TIME_WAIT/){print $1} '
$ netstat|head -5|awk '($3==0 || $6 ~/TIME_WAIT/){print $1} '
$ netstat|head -5|awk '{if($3==0 || $NF ~/TIME_WAIT/){print $1;}else{print $2;}} '$ awk '/muyw/' /etc/passwd #类似grep
muyw:x:601:500::/home/muyw:/bin/bash
$ awk '{if($0~/muyw/){print $0}}' /etc/passwd
$ awk '{if($0!~/muyw/){print $0}}' /etc/passwd
$ awk '!/muyw/' /etc/passwd #类似grep $ netstat | head -10| awk '(NR>2){print >$6}'
$ cat TIME_WAIT
tcp 0 0 amd10:39076 amd200:ssh TIME_WAIT
tcp 0 0 amd10:39698 amd38:ssh TIME_WAIT
tcp 0 0 amd10:40589 amd40:ssh TIME_WAIT
tcp 0 0 amd10:32911 com8:ssh TIME_WAIT
tcp 0 0 amd10:56451 amd10:46701 TIME_WAIT
tcp 0 0 amd10:41556 amd10:46701 TIME_WAIT
tcp 0 0 amd10:47849 amd10:46701 TIME_WAIT
tcp 0 0 amd10:38192 amd201:ssh TIME_WAIT
$ netstat | head -10| awk '(NR>2){print $2,$3 >$6}'
$ netstat | head -10| awk '(NR!=1){if($6 ~/TIME|ESTABLISHED/) {print $0> "1.txt";}else if($6 ~ /LISTEN/) {print > "2.txt";}else {print $0> "3.txt";}}'
$ netstat | head -10| awk '(NR!=1){
if($6 ~/TIME|ESTABLISHED/) {print $0> "1.txt";
}else if($6 ~ /LISTEN/) {print > "2.txt";
}else {print $0> "3.txt";}}'$ ls -l *.dat|awk '{sum+=$5} END{print sum}'
715
$ ls -l *.dat| awk 'BEGIN{sum=0}{sum=sum+$5}END{print sum;}'$ netstat | head -10 |awk '(NR!=1){a[$6]=a[$6]+1;} END {for (i in a) print i ", " a[i];}'
Foreign, 1
TIME_WAIT, 8muyw 31990 0.0 0.0 65604 984 pts/5 R+ 13:54 0:00 ps aux
$ ps aux | awk 'NR!=1{a[$1]+=$6;} END { for(i in a) print i ", " a[i]"KB";}'
rpc, 580KB
gaot, 18236KB
tianxx, 7668KB
muyw, 10316KB
apache, 62504KB
$ x=5
$ y=10
$ export y
$ awk -v val=$x 'BEGIN{print val,ENVIRON["y"],'${x}'}'在上面我们可以看到一个END关键字。END的意思是“处理完所有的行的标识”，即然说到了END就有必要介绍一下BEGIN，这两个关键字意味着执行前和执行后的意思，语法如下：
学生成绩表：
$ cat score.txt
Marry 2143 78 84 77
Jack 2321 66 78 45
Tom 2122 48 77 71
Mike 2537 87 97 95
Bob 2415 40 57 62$ cat cal.awk
#!/bin/awk -f
#运行前
BEGIN {
math = 0
english = 0
computer = 0
printf "NAME NO. MATH ENGLISH COMPUTER TOTAL\n"
printf "---------------------------------------------\n"
}
#运行中
{
math+=$3
english+=$4
computer+=$5
printf "%-6s %-6s %4d %8d %8d %8d\n", $1, $2, $3,$4,$5, $3+$4+$5
}
#运行后
END {
printf "---------------------------------------------\n"
printf " TOTAL:%10d %8d %8d \n", math, english, computer
printf "AVERAGE:%10.2f %8.2f %8.2f\n", math/NR, english/NR, computer/NR
}
#: 可以增加变量 nstudent