linux学习lesson28

目录

1 awk命令

---

1 awk命令

• 拷贝练习文件

[[email protected] dir9]# cp /etc/passwd ./testpasswd

• 打印第一个字段

[[email protected] dir9]# head -n2 testpasswd | awk -F ':' '{print $1}'
ROOT
bin

• 打印整行

[[email protected] dir9]# head -n2 testpasswd | awk -F ':' '{print $0}'
ROOT:x:0:0:roooot:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin

• 打印第一字段，第二字段，第三字段，第四字段，打印的分隔符是"#"

[[email protected] dir9]# awk -F ':' '{print $1"#"$2"#"$3"#"$4}' testpasswd
ROOT#x#0#0
bin#x#1#1
daemon#x#2#2
adm#x#3#4
lp#x#4#7
sync#x#5#0
shutdown#x#6#0
halt#x#7#0
mail#x#8#12
operator#x#11#0
games#x#12#100
ftp#x#14#50
nobody#x#99#99
avahi-autoipd#x#170#170
systemd-bus-proxy#x#999#997
systemd-network#x#998#996
dbus#x#81#81
polkitd#x#997#995
tss#x#59#59
postfix#x#89#89
sshd#x#74#74
user#x#1000#1000
user1#x#1001#1001
user2#x#1002#1100
user3#x#1111#1100
user5#x#1112#1112
user6#x#1113#1113
ntp#x#38#38
tcpdump#x#72#72
BUS123###

• 匹配字符"oo"

[[email protected] dir9]# awk '/oo/' testpasswd
ROOT:x:0:0:roooot:/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

• 第一个字段匹配字符"adm"

[[email protected] dir9]# awk -F ':' '$1 ~/adm/' testpasswd
adm:x:3:4:adm:/var/adm:/sbin/nologin

• 匹配字符"root"的打印第一个字段和第三个字段；匹配字符"adm"的打印第一个字段、第三个字段和第四个字段

[[email protected] dir9]# awk -F ':' '/root/ {print $1,$3} /adm/ {print $1,$3,$4}' testpasswd
ROOT 0
adm 3 4
operator 11

• 第3个字段等于字符值为0的行

[[email protected] dir9]# awk -F ':' '$3=="0"' testpasswd
ROOT:x:0:0:roooot:/root:/bin/bash

• 第3个字段大于等于字符值为500的行（以ASCII码形式）

[[email protected] dir9]# awk -F ':' '$3>="500"' testpasswd
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:/sbin/nologin
systemd-network:x:998:996:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:997:995:User for polkitd:/:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin

• 第3个字段数值大于等于500的行

[[email protected] dir9]# awk -F ':' '$3>=500' testpasswd
systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:/sbin/nologin
systemd-network:x:998:996:systemd Network Management:/:/sbin/nologin
polkitd:x:997:995:User for polkitd:/:/sbin/nologin
user:x:1000:1000::/home/user:/bin/bash
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1100::/home/user2:/bin/bash
user3:x:1111:1100::/home/user3:/bin/bash
user5:x:1112:1112::/home/user5:/bin/bash
user6:x:1113:1113::/home/user6:/bin/bash

• 第7个字段值字符为"/sbin/nologin"的行

[[email protected] dir9]# awk -F ":" '$7!="/sbin/nologin"' testpasswd
ROOT:x:0:0:roooot:/root:/bin/bash
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
user:x:1000:1000::/home/user:/bin/bash
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1100::/home/user2:/bin/bash
user3:x:1111:1100::/home/user3:/bin/bash
user5:x:1112:1112::/home/user5:/bin/bash
user6:x:1113:1113::/home/user6:/bin/bash
BUS123

• 打印第4个字段大于第3个字段的行

[[email protected] dir9]# awk -F ":" '$3>$4' testpasswd
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
operator:x:11:0:operator:/root:/sbin/nologin
systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:/sbin/nologin
systemd-network:x:998:996:systemd Network Management:/:/sbin/nologin
polkitd:x:997:995:User for polkitd:/:/sbin/nologin
user3:x:1111:1100::/home/user3:/bin/bash

• 打印第3个字段大于第5个字段并且第3个字段大于字符值为7的行

[[email protected] dir9]# awk -F ":" '$3>"5" && $3<"7"' testpasswd
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin

• 打印第3个字段大于1000的数值或者第7个字段等于字符"/bin/bash"的行

[[email protected] dir9]# awk -F ":" '$3>1000||$7=="/bin/bash"' testpasswd
ROOT:x:0:0:roooot:/root:/bin/bash
user:x:1000:1000::/home/user:/bin/bash
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1100::/home/user2:/bin/bash
user3:x:1111:1100::/home/user3:/bin/bash
user5:x:1112:1112::/home/user5:/bin/bash
user6:x:1113:1113::/home/user6:/bin/bash

• 打印第1,3,4个字段，间隔符为"#"

[[email protected] dir9]# head -5 testpasswd | awk -F ":" '{OFS="#"} {print $1,$3,$4}'
ROOT#0#0
bin#1#1
daemon#2#2
adm#3#4
lp#4#7

• 条件判断：第3个字段大于1000的值，打印第1,3,4个字段，间隔符为"#"

[[email protected] dir9]# awk -F ":" '{OFS="#"} { if($3>1000) {print $1,$3,$4}}' testpasswd
user1#1001#1001
user2#1002#1100
user3#1111#1100
user5#1112#1112
user6#1113#1113

• 以":"分隔，打印字段数

[[email protected] dir9]# head -n5 testpasswd | awk -F ":" '{print NF}'
7
7
7
7
7

• 以":"分隔，打印行号

[[email protected] dir9]# head -n5 testpasswd | awk -F ":" '{print NR}'
1
2
3
4
5

• 打印行号大于20的行

[[email protected] dir9]# awk 'NR>20' testpasswd
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
user:x:1000:1000::/home/user:/bin/bash
user1:x:1001:1001::/home/user1:/bin/bash
user2:x:1002:1100::/home/user2:/bin/bash
user3:x:1111:1100::/home/user3:/bin/bash
user5:x:1112:1112::/home/user5:/bin/bash
user6:x:1113:1113::/home/user6:/bin/bash
ntp:x:38:38::/etc/ntp:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
BUS123

• 打印行号小于20并且匹配字符"roo"的行

[[email protected] dir9]# awk 'NR<20 && $1 ~ /roo/' testpasswd
ROOT:x:0:0:roooot:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

• 打印第1个字段等于字符为"bin"

[[email protected] dir9]# head -n3 testpasswd | awk -F ":" '$1=="bin"'
bin:x:1:1:bin:/bin:/sbin/nologin

• 计算第3个字段的总和

[[email protected] dir9]# awk -F ':' '{sum=sum+$3} END {print sum}' testpasswd
10088

条件匹配：打印第1个字段等于字符"bin"的行

[[email protected] dir9]# awk -F ':' '$1=="bin" {print $0}' testpasswd
bin:x:1:1:bin:/bin:/sbin/nologin

扩展
所有练习题练练 http://www.apelearn.com/study_v2/chapter14.html