当天练习题:
基本正则表达式练习题
1.显示/proc/meminfo文件中以大小s开头的行;(要求:使用两种方式) 可有四种方式
[root@CentOS7 ~]# cat /proc/meminfo | grep -E "^(s|S)" SwapCached: 0 kB SwapTotal: 2097148 kB SwapFree: 2097148 kB Shmem: 7320 kB Slab: 74112 kB SReclaimable: 28308 kB SUnreclaim: 45804 kB [root@CentOS7 ~]# cat /proc/meminfo | grep -E -i "^s" SwapCached: 0 kB SwapTotal: 2097148 kB SwapFree: 2097148 kB Shmem: 7320 kB Slab: 74112 kB SReclaimable: 28308 kB SUnreclaim: 45804 kB [root@CentOS7 ~]# cat /proc/meminfo | grep -E "^[sS]" SwapCached: 0 kB SwapTotal: 2097148 kB SwapFree: 2097148 kB Shmem: 7320 kB Slab: 74112 kB SReclaimable: 28308 kB SUnreclaim: 45804 kB [root@CentOS7 ~]# cat /proc/meminfo | grep -e "^s" -e "^S" SwapCached: 0 kB SwapTotal: 2097148 kB SwapFree: 2097148 kB Shmem: 7320 kB Slab: 74112 kB SReclaimable: 28308 kB SUnreclaim: 45804 kB [root@CentOS7 ~]#
2.显示/etc/passwd文件中不以/bin/bash结尾的行
[root@CentOS6 ~]# grep -E -v "/bin/bash$" /etc/passwd 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 uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin games:x:12:100:games:/usr/games:/sbin/nologin gopher:x:13:30:gopher:/var/gopher:/sbin/nologin ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin usbmuxd:x:113:113:usbmuxd user:/:/sbin/nologin rpc:x:32:32:Rpcbind Daemon:/var/cache/rpcbind:/sbin/nologin rtkit:x:499:499:RealtimeKit:/proc:/sbin/nologin avahi-autoipd:x:170:170:Avahi IPv4LL Stack:/var/lib/avahi-autoipd:/sbin/nologin vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin abrt:x:173:173::/etc/abrt:/sbin/nologin rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin haldaemon:x:68:68:HAL daemon:/:/sbin/nologin ntp:x:38:38::/etc/ntp:/sbin/nologin apache:x:48:48:Apache:/var/www:/sbin/nologin saslauth:x:498:76:Saslauthd user:/var/empty/saslauth:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin gdm:x:42:42::/var/lib/gdm:/sbin/nologin pulse:x:497:495:PulseAudio System Daemon:/var/run/pulse:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin tcpdump:x:72:72::/:/sbin/nologin nologin:x:510:514::/home/nologin:/sbin/nologin [root@CentOS6 ~]#
3.显示用户rpc默认的shell程序
[root@CentOS6 ~]# grep -E "^rpc\>" /etc/passwd #取出rpc用户信息 rpc:x:32:32:Rpcbind Daemon:/var/cache/rpcbind:/sbin/nologin [root@CentOS6 ~]# grep -E "^rpc\>" /etc/passwd | cut -d: -f7 #取出shell /sbin/nologin [root@CentOS6 ~]#
4.找出/etc/passwd中的两位或三位数
[root@CentOS6 ~]# grep -o "\<[0-9]\{2,3\}\>" /etc/passwd 12 10 14 11 12 100 13 30 14 50 99 99 81 81 113 113 32 32 499 499 170 170 69 69 173 173 29 29 68 68 38 38 48 48 498 76 89 89 27 27 42 42 497 495 74 74 72 72 500 500 501 501 502 503 503 507 504 508 505 509 506 510 507 511 508 512 509 513 510 514 511 515 512 516 [root@CentOS6 ~]#
5.显示/etc/grub.conf文件中,至少以一个空白字符开头的且后面存非空白字符的行
[root@CentOS6 ~]# grep "^[[:space:]]\+[^[:space:]]" /etc/grub.conf root (hd0,0) kernel /vmlinuz-2.6.32-642.el6.x86_64 ro root=UUID=f4d977bb-af76-4617-b07f-9c70ae42a056 rd_NO_LUKS rd_NO_LVM.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet initrd /initramfs-2.6.32-642.el6.x86_64.img [root@CentOS6 ~]#
6.找出"netstat -tan"命令的结果中以'LISTEN'后跟0、1或多个空白字符结尾的行
[root@CentOS7 ~]# netstat -tan | grep -o "LISTEN[[:space:]]*$" LISTEN LISTEN LISTEN LISTEN LISTEN LISTEN LISTEN [root@CentOS7 ~]#
7.添加用户bash、testbash、basher以及nologin(其shell为/sbin/nologin),而后找出/etc/passwd文件中用户名同shell名的行
[root@CentOS6 ~]# grep "^\([^:]\+\>\).*\<\1\>$" /etc/passwd sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt bash:x:507:511::/home/bash:/bin/bash nologin:x:510:514::/home/nologin:/sbin/nologin [root@CentOS6 ~]#
扩展正则表达式
1.显示当前系统root、mage或wang用户的UID和默认shell
[root@CentOS6 ~]# cat /etc/passwd | grep -E "^(root|mage|wang)\>" #匹配出root、mage、wang三个用户信息 root:x:0:0:root:/root:/bin/bash mage:x:511:515::/home/mage:/bin/bash wang:x:512:516::/home/wang:/bin/bash [root@CentOS6 ~]# cat /etc/passwd | grep -E "^(root|mage|wang)\>" | cut -d: -f1,3,7 #取出用户名、UID、shell root:0:/bin/bash mage:511:/bin/bash wang:512:/bin/bash [root@CentOS6 ~]#
2.找出/etc/rc.d/init.d/functions文件中行首为某单词(包括下划线)后面跟一个小括号的行
[root@CentOS6 ~]# cat /etc/rc.d/init.d/functions | grep -E "[_[:alpha:]]+\(\)" fstab_decode_str() { checkpid() { __readlink() { __fgrep() { __kill_pids_term_kill_checkpids() { __kill_pids_term_kill() { __umount_loop() { __source_netdevs_fstab() { __source_netdevs_mtab() { __umount_loopback_loop() { __find_mounts() { __pids_var_run() { __pids_pidof() { daemon() { killproc() { pidfileofproc() { pidofproc() { status() { echo_success() { echo_failure() { echo_passed() { echo_warning() { update_boot_stage() { success() { failure() { passed() { warning() { action() { action_silent() { strstr() { confirm() { get_numeric_dev() { is_ignored_file() { is_true() { is_false() { apply_sysctl() { key_is_random() { find_crypto_mount_point() { init_crypto() { [root@CentOS6 ~]#
3.使用egrep取出/etc/rc.d/init.d/functions中其基名
[root@CentOS6 ~]# echo /etc/rc.d/init.d/functions/ | grep -E -o "[^/]+/?$" #匹配以非斜线结尾的字符至少一次 functions/ [root@CentOS6 ~]# echo /etc/rc.d/init.d/functions/ | grep -E -o "[^/]+/?$" | grep -E -o "[^/]+" #过滤掉结尾的/ functions [root@CentOS6 ~]#
4.使用egrep取出上面路径的目录名
[root@CentOS6 ~]# echo /etc/rc.d/init.d/functions/ | grep -E -o "^/.*[^/]" #首先过滤掉结尾的/ /etc/rc.d/init.d/functions [root@CentOS6 ~]# echo /etc/rc.d/init.d/functions/ | grep -E -o "^/.*[^/]" | grep -E -o "^/.*/" #取出目录名 /etc/rc.d/init.d/ [root@CentOS6 ~]#
5.统计以root身份登录的每个远程主机IP地址的登录次数
[root@CentOS7 ~]# last | grep -E -o "^root\>.*([[:digit:]]+\.){3}[[:digit:]]+" | tr -s ' ' | cut -d' ' -f1,3 #取出当前系统已root身份登录的IP root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 172.18.19.139 root 192.168.0.107 root 192.168.0.109 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 root 10.1.250.60 [root@CentOS7 ~]# last | grep -E -o "^root\>.*([[:digit:]]+\.){3}[[:digit:]]+" | tr -s ' ' | cut -d' ' -f1,3 | sort | uniq -c #取出重复次数 22 root 10.1.250.60 1 root 172.18.19.139 1 root 192.168.0.107 1 root 192.168.0.109 [root@CentOS7 ~]#
6.利用扩展正则表达式分别表示0-9、10-99、100-199、200-249、250-255
[root@CentOS6 ~]# grep "[0-9] [1-9][0-9] 1[0-9]{2} 2[0-4][0-9] 25[0-5]"
7.显示ifconfig命令结果中所有IPv4地址
[root@CentOS6 ~]# ifconfig | grep -E -o "(\<([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>\.){3}\<([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>" 10.1.252.233 10.1.255.255 255.255.0.0 127.0.0.1 255.0.0.0 [root@CentOS6 ~]#
作业练习题:
1.取本机ip地址
[root@CentOS6 ~]# ifconfig | grep -E -o "(\<([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>\.){3}\<([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\>" 10.1.252.233 10.1.255.255 255.255.0.0 127.0.0.1 255.0.0.0 [root@CentOS6 ~]#
2.取各分区利用率的数值
[root@CentOS6 ~]# df | tr -s ' ' | cut -d' ' -f5 Use% 10% 1% 19% 1% [root@CentOS6 ~]#
3.统计/etc/init.d/functions 文件中每个单词出现的次数,并按频率从高到低显示
[root@CentOS6 ~]# cat /etc/rc.d/init.d/functions | tr -sc '[:alpha:]' '\n' | sort | uniq -c | sort -nr -t' ' -k1 83 if 77 then 75 pid 73 echo 72 fi 61 return 57 dev 54 file 50 n 46 local 42 kill 39 z 36 base 35 remaining 31 a 30 d 27 in 25 null 24 key 23 is 23 fstab 23 done 23 do 23 awk 22 pids 22 list 21 for 21 BOOTUP 20 to 20 p 20 dst 19 shift ...
4.正则表达式表示身份证号
[root@CentOS7 ~]# egrep "\<((1[1-5])|(2[1-3])|(3[1-7])|(4[1-6])|(5[0-4])|(6[1-5])|(71|81|82))([0-9]){4}(19|20)([0-9]){2}((0[1-9])|(1[0-2]))(0[1-9]|([0-9])|(2[0-9])|(3[0-1]))([0-9]){3}([0-9]|X)\>" number.txt 210905197807210546 370205197405213513 372922198012224773 370722197812222517 230803197906010035 152801198703025310 511428196305026357 [root@CentOS7 ~]#
5.正则表达式表示手机号
[root@CentOS7 ~]# grep -E -o "(\+86)?1[38][0-9]{9}|14[57][0-9]{8}|15[0-35-9][0-9]{8}|17[0678][0-9]{8}" iphone.txt +8613868233891 15003107238 [root@CentOS7 ~]#
6.正则表达式表示邮箱
[root@CentOS7 ~]# egrep "\<([[:alnum:]]+(-|_)*[[:alnum:]]*)\>@([[:alnum:]]+\.)+[[:alnum:]]+" mail.txt 993667135@qq.com servername@163.com [root@CentOS7 ~]#
7.正则表达式表示QQ号
[root@CentOS7 ~]# grep -E -o '\b[1-9][0-9]{4,12}\b' qq.txt 333449 521521 796898 765423 93796117258 [root@CentOS7 ~]#
原创文章,作者:zhai796898,如若转载,请注明出处:http://www.178linux.com/30996