grep：过滤文本
sed：修改文本
awk：处理文本
1、找出/proc/meminfo文件中以s开头的行，至少用三种方式忽略大小写
[root@localhost ~]# grep -E '^[sS]' /proc/meminfo [root@localhost ~]# sed -r -n '/^[sS]/p' /proc/meminfo # -n:取消默认输出 [root@localhost ~]# awk '/^[sS]/{print $0}' /proc/meminfo SwapCached: 0 kB SwapTotal: 0 kB SwapFree: 0 kB Shmem: 7676 kB Slab: 45744 kB SReclaimable: 23440 kB SUnreclaim: 22304 kB
2、显示当前系统上的以root，centos或者user开头的信息
[root@localhost ~]# grep -rE '^(root|centos|user)' /etc/ /etc/pki/ca-trust/extracted/README:root CA certificates. /etc/pki/ca-trust/extracted/java/README:root CA certificates. /etc/pki/ca-trust/extracted/openssl/README:root CA certificates. /etc/pki/ca-trust/extracted/pem/README:root CA certificates. /etc/yum/vars/contentdir:centos
3、找出/etc/init.d/functions文件下包含小括号的行
[root@localhost ~]# grep -E '\(|\)' /etc/init.d/functions /etc/init.d/*|/etc/rc.d/init.d/*) systemctl_redirect () { start) s=$"Starting $prog (via systemctl): " stop) s=$"Stopping $prog (via systemctl): " reload|try-reload)
4、输出指定目录的基名
[root@localhost sysconfig]# pwd | awk -F/ '{print $NF}' sysconfig
5、找出网卡信息中包含的数字
[root@localhost ~]# grep -oE '[0-9]+' /etc/sysconfig/network-scripts/ifcfg-eth[01] /etc/sysconfig/network-scripts/ifcfg-eth0:4 /etc/sysconfig/network-scripts/ifcfg-eth0:6 /etc/sysconfig/network-scripts/ifcfg-eth0:6 /etc/sysconfig/network-scripts/ifcfg-eth0:6 /etc/sysconfig/network-scripts/ifcfg-eth0:6 /etc/sysconfig/network-scripts/ifcfg-eth0:6 /etc/sysconfig/network-scripts/ifcfg-eth0:0 /etc/sysconfig/network-scripts/ifcfg-eth0:3 /etc/sysconfig/network-scripts/ifcfg-eth0:7 /etc/sysconfig/network-scripts/ifcfg-eth0:60 /etc/sysconfig/network-scripts/ifcfg-eth0:479
6、找出/etc/passwd下每种解析器的用户个数
# 数组：{"bash":10,"sh":9,"zsh":1}
[root@localhost ~]# awk -F: '{arr[$NF]++}END{for(i in arr){print i,arr[i]}}' /etc/passwd
/bin/sync 1
/bin/bash 7
/sbin/nologin 22
/sbin/halt 1
/sbin/shutdown 1
7、获取网卡中的ip，用三种方式实现
[root@localhost ~]# ip a | grep -oE '([0-9]{1,3}\.){3}[0-9]{1,3}' [root@localhost ~]# ip a | sed -r -n '/([0-9]{1,3}\.){3}[0-9]{1,3}/p' [root@localhost ~]# ip a | awk '/([0-9]{1,3}\.){3}[0-9]{1,3}/{if(NR==3){print $2}else{print $2,$4}}' 127.0.0.1/8 192.168.15.102/24 192.168.15.255 172.16.1.102/20 172.16.15.255
8、搜索/etc目录下，所有的.html或.php文件中main函数出现的次数
# 反引号（``）将里面的结果作为操作对象；xargs：将内容打印成行 [root@localhost ~]# grep -rE 'main' `find /etc/ -name "*.html" -o -name "*.php" | xargs` |wc -l 1134
9、过滤掉php.ini中注释的行和空行
# ^$：空行 [root@localhost ~]# grep -vE '^\ *;|^$' /etc/php.ini [PHP] engine = On short_open_tag = Off asp_tags = Off precision = 14 output_buffering = 4096 zlib.output_compression = Off
10、找出文件中至少有一个空格的行
[root@localhost ~]# grep -E '\ +' /etc/php.ini
11、过滤文件中以#开头的行，后面至少有一个空格
[root@localhost ~]# grep -E '^#\ +' /etc/fstab # /etc/fstab # Created by anaconda on Wed Dec 8 16:57:29 2021 # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
12、查询出/etc目录中包含多少个root
[root@localhost ~]# grep -roE 'root' /etc/ | wc -l 600
13、查询出所有的qq邮箱
[root@localhost ~]# grep -E '[0-9A-Za-z-_]+@qq\.com'
14、查询系统日志中所有的error
[root@localhost ~]# grep -E 'error' /var/log/messages
15、删除某文件中以s开头的行的最后一个词
[root@localhost ~]# grep -Ei '^s' 3.txt | grep -oE '[0-9A-Za-z]+' | xargs | awk '{for(i=0;i<(NF-1);i++){print $i}}' sdfdf jkjdf sdf sdfdf
正确答案
[root@localhost ~]# grep -Ei '^s' 3.txt | sed -r 's/[0-9a-zA-Z]+$//g' sdfdf jkjdf
16、删除一个文件中的所有数字
[root@localhost ~]# sed -r 's/[0-9]//g' 3.txt
17、显示奇数行
[root@localhost ~]# awk -F: 'NR%2==1{print $0}' /etc/passwd root:x:0:0:root:/root:/bin/bash daemon:x:2:2:daemon:/sbin:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
18、删除passwd文件中以bin开头的行到nobody开头的行
[root@localhost ~]# sed -r '/^bin/,/^nobody/d' /etc/passwd root:x:0:0:root:/root:/bin/bash systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:998:User for polkitd:/:/sbin/nologin
19、从指定行开始，每隔两行显示一次空行
[root@localhost ~]# awk -F: '{n=5;if(NR<=n){print $0}else{if((NR-5)%2==0){print " "}print $0}}' /etc/passwd root:x:0:0:root:/root:/bin/bash 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 halt:x:7:0:halt:/sbin:/sbin/halt mail:x:8:12:mail:/var/spool/mail:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin
20、每隔5行打印一个空行
[root@localhost ~]# awk -F: '{if(NR%5==0){print " "}print $0}' /etc/passwd root:x:0:0:root:/root:/bin/bash 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 halt:x:7:0:halt:/sbin:/sbin/halt mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
21、不显示指定字符的行
[root@localhost ~]# grep -Ev 'l' 3.txt jsdfds fersdf jere sdfdf jkjdf sdf
22、将文件中1到5行中aaa替换成AAA
[root@localhost ~]# sed -r '1,5s/aaa/AAA/g' 3.txt jakdfj djsfj jklll feefAAAlljj jjll fjklkjl AAAfds fersdf jere sdfdf jkjdf sdf aaadfdf
23、显示用户id为奇数的行
[root@localhost ~]# awk -F: '$3%2==1{print $0}' /etc/passwd bin:x:1:1:bin:/bin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync halt:x:7:0:halt:/sbin:/sbin/halt operator:x:11:0:operator:/root:/sbin/nologin
24、显示系统普通用户，并打印系统用户名和id
# id=0：超级用户；0<id<1000：系统用户；id>=1000：普通用户 [root@localhost ~]# awk -F: '$3>=1000{print $1,$3}' /etc/passwd test 1000 test03 1001 tuser1 1002 tuser2 1003 tuser3 1004
25、统计nginx日志中独立用户数（ip维度计算）
[root@localhost ~]# awk '/([0-9]{1,3}\.){3}[0-9]{1,3}/{arr[$1]++}END{for(i in arr){print i}}' access.log 49.232.15.254 107.189.12.88 167.248.133.41 90.113.136.249 159.89.26.34 4.71.37.46 168.228.151.191 2.56.59.221 3.25.221.59 45.137.23.232
26、统计php.ini中每个词的个数
[root@localhost ~]# grep -oE '[0-9A-Za-z]+' 3.txt | awk '{arr[$1]++}END{for(i in arr){printf "%-15s | %-5d\n",i,arr[i]}}' aaadfdf | 1 sdfdf | 1 feefaaalljj | 1 jklll | 1 jakdfj | 1 jkjdf | 1 aaafds | 1 fjklkjl | 1 fersdf | 1 jere | 1 jjll | 1 sdf | 1 djsfj | 1 jkll | 3
