6-3 9 awk

9.6/9.7 awk

幾種用法

awk '{print $1}' 1.txt  \\輸出第一列
awk -F ':' '{print $1,$3,$5}' test.txt \\指定分隔符：輸出1,3,5列
awk -F ':' '{print $1"#"$3"#"$5}' test.txt
awk '/oo/' test.txt
awk -F ':' "$1 ~ /oo/' test.txt
awk -F ':' '$1 ~ /oo+/' test.txt
awk -F ':' '$1 ~ /o+/' test.txt
awk -F ':' '/root/ {print $1,$3} /user/ {print $3,$4}' test.txt
awk -F ':' '/root/ {print $1,$3} /user/ {print $1,$3,$4}' test.txt
awk -F ':' '$3==0' test.txt
awk -F ':' '$3>=1000 {print $0}' test.txt
awk -F ':' '$7!="/sbin/nologin" {print $0}' test.txt

eg

root@lixiang01:~# awk -F ':' '{print $1,$3,$5}' test.txt | head -2
root 0 root
bin 1 bin

awk -F 指定分隔符 print中的都好打印爲空格,其餘分隔符不變

root@lixiang01:~# awk -F ':' '{print $1"#"$3"#"$5}' test.txt | head -2
root#0#root
bin#1#bin

awk的正則匹配與sed的相似

root@lixiang01:~# awk '/oo/' test.txt
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin

root@lixiang01:~# awk -F ':' '$1 ~ /oo/' test.txt
root:x:0:0:root:/root:/bin/bash

root@lixiang01:~# awk -F ':' '$1 ~ /o+/' test.txt |head -2
root:x:0:0:root:/root:/bin/bash
daemon:x:2:2:daemon:/sbin:/sbin/nologin

awk匹配能夠屢次執行

root@lixiang01:~# awk -F ':' '/root/ {print $1,$3} /user/ {print $1,$3,$4}' test.txt
root 0
operator 11
tss 59 59
user1 1001 1001
user2 1002 1006
user3 1004 1005
root@lixiang01:~# grep -E 'root|user' test.txt

root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1006::/home/user2:/bin/bash
user3:x:1004:1005::/home/user3:/bin/bash

awk的匹配可使用「|」用爲或者，｛print $0｝爲默認輸出，可省

root@lixiang01:~# awk -F ':' '/root|user/ {print $0}' test.txt
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1006::/home/user2:/bin/bash
user3:x:1004:1005::/home/user3:/bin/bash

比較數字時不能加雙引號

root@lixiang01:~# awk -F ':' '$3>=1000' test.txt
lixiang:x:1000:1000::/home/lixiang:/bin/bash
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1006::/home/user2:/bin/bash
user3:x:1004:1005::/home/user3:/bin/bash
axiang:x:1010:1011::/home/axiang:/bin/bash
root@lixiang01:~# awk -F ':' '$3>="1000"' test.txt | head -3
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

root@lixiang01:~# awk -F ':' '$7!="/bin/bash"' test.txt
bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

擴展 把這裏面的全部練習題作一下 http://www.apelearn.com/study_v2/chapter14.html