馬哥教育網絡班20期+第5周課程練習
1、顯示/boot/grub/grub.conf中以至少一個空白字符開頭的行；
# grep -E "^[[:space:]]+" /boot/grub/grub.conf 實例演示 [root@C664BSLab ~]# grep -E "^[[:space:]]+" /boot/grub/grub.conf root (hd0,0) kernel /vmlinuz-2.6.32-573.el6.x86_64 ro root=/dev/mapper/vg_c664bslab-lv_root rd_NO_LUKS.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=vg_c664bslab/lv_swap KEYBOARDTYPE=pc KEYTABLE=us rd_LVM_LV=vg_c664bslab/lv_root rd_NO_DM rhgb quiet initrd /initramfs-2.6.32-573.el6.x86_64.img
2、顯示/etc/rc.d/rc.sysinit文件中以#開頭，后面跟至少一個空白字符，而后又有至少一個非空白字符的行；
# grep -E "^#[[:space:]]+[^[:space:]]+" /etc/rc.d/rc.sysinit 實例演示 [root@C664BSLab ~]# grep -E "^#[[:space:]]+[^[:space:]]+" /etc/rc.d/rc.sysinit # /etc/rc.d/rc.sysinit - run once at boot time # Taken in part from Miquel van Smoorenburg's bcheckrc. # Check SELinux status # Print a text banner. # Only read this once.
3、打出netstat -tan命令執行結果中以‘LISTEN’，后或跟空白字符結尾的行；
# netstat -tan | grep -E "LISTEN[[:space:]]*$" 實例演示 [root@C664BSLab ~]# netstat -tan | grep -E "LISTEN[[:space:]]*$" tcp 0 0 0.0.0.0:50048 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp 0 0 :::54890 :::* LISTEN tcp 0 0 :::111 :::* LISTEN tcp 0 0 :::80 :::* LISTEN tcp 0 0 :::22 :::* LISTEN tcp 0 0 ::1:631 :::* LISTEN tcp 0 0 ::1:25 :::* LISTEN
4、添加用戶bash, testbash, basher, nologin (此一個用戶的shell為/sbin/nologin)，而后找出當前系統上其用戶名和默認shell相同的用戶的信息；
# useradd bash # useradd testbash # useradd basher # useradd -s /sbin/nologin nologin # grep -E "^([[:alpha:]]+\>).*\1$" /etc/passwd 實例演示 [root@C664BSLab ~]# useradd bash [root@C664BSLab ~]# useradd testbash [root@C664BSLab ~]# useradd basher [root@C664BSLab ~]# grep -E "^([[:alpha:]]+\>).*\1$" /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:502:502::/home/bash:/bin/bash nologin:x:505:505::/home/nologin:/sbin/nologin
5、顯示當前系統上root、fedora或user1用戶的默認shell；
# grep -E "^(root|fedora|user1)\>" /etc/passwd | cut -d: -f1,7 實例演示 [root@C664BSLab ~]# grep -E "^(root|fedora|user1)\>" /etc/passwd | cut -d: -f1,7 root:/bin/bash fedora:/bin/bash user1:/bin/bash
6、找出/etc/rc.d/init.d/functions文件中某單詞后面跟一組小括號的行，形如：hello()；
# grep -E "\<[[:alpha:]]+\>\(\)" /etc/rc.d/init.d/functions 實例演示 [root@C664BSLab ~]# grep -E -o "\<[[:alpha:]]+\>\(\)" /etc/rc.d/init.d/functions checkpid() daemon() killproc() pidfileofproc() pidofproc() status()
7、使用echo命令輸出一個絕對路徑，使用grep取出其基名；
擴展：取出其路徑名
# echo "/etc/rc.d/init.d/functions" | grep -E -o "[^/][[:alpha:]]+/?$" # echo "/etc/rc.d/init.d/functions" | grep -E -o "^(/.*/)" 實例演示 [root@C664BSLab ~]# echo "/etc/rc.d/init.d/functions" | grep -E -o "[^/][[:alpha:]]+/?$" functions [root@C664BSLab ~]# echo "/etc/rc.d/init.d/functions" | grep -E -o "(/.*/)" /etc/rc.d/init.d/
8、找出ifconfig命令結果中的1-255之間數字；
# ifconfig | grep -E -o "\<([1-9][0-9]?|[1][0-9][0-9]|2[0-4][0-9]|25[0-5])\>" 實例演示 [root@C664BSLab ~]# ifconfig | grep -E -o "\<([1-9][0-9]?|[1][0-9][0-9]|2[0-4][0-9]|25[0-5])\>" 29 192 168 225 136 192 168 225
9、挑戰題：寫一個模式，能匹配合理的IP地址；
# ifconfig | grep -E -o "([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])" 實例演示 [root@C664BSLab ~]# ifconfig | grep -E -o "([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])\.([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])" 192.168.225.136 192.168.225.255 255.255.255.0 127.0.0.1 255.0.0.0
10、挑戰題：寫一個模式，能匹配出所有的郵件地址；
# echo "This is a test e-mail address test2_Ecd@test.com" | grep -E -o "[[:alnum:]_]+\@[[:alpha:]]+\.[[:alpha:]]+" 實例演示 [root@C664BSLab ~]# echo "This is a test e-mail address test2_Ecd@test.com" | grep -E -o "[[:alnum:]_]+\@[[:alpha:]]+\.[[:alpha:]]+" test2_Ecd@test.com
11、查找/var目錄下屬主為root，且屬組為mail的所有文件或目錄；
# find /var -user root -group mail -ls 實例演示 [root@C664BSLab ~]# find /var -user root -group mail -ls 1049287 4 drwxrwxr-x 2 root mail 4096 Jul 5 08:45 /var/spool/mail
12、查找當前系統上沒有屬主或屬組的文件；
# find / \( -nouser -o -nogroup \) -ls 實例演示 [root@C664BSLab ~]# find / \( -nouser -o -nogroup \) -ls 262145 4 drwx------ 2 508 508 4096 Jul 5 10:08 /home/tuser1 262149 0 -rw-rw-r-- 1 508 508 0 Jul 5 10:08 /home/tuser1/abc.txt 1049732 0 -rw-rw---- 1 508 mail 0 Jul 5 10:08 /var/spool/mail/tuser1
進一步：查找當前系統上沒有屬主或屬組，且最近3天內曾被訪問過的文件或目錄；
# find / \( -nouser -o -nogroup \) -a -atime -3 -ls 實例演示 [root@C664BSLab ~]# find / \( -nouser -o -nogroup \) -a -atime -3 -ls 262145 4 drwx------ 2 508 508 4096 Jul 5 10:08 /home/tuser1 262148 4 -rw-r--r-- 1 508 508 176 May 11 07:21 /home/tuser1/.bash_profile 262150 4 -rw------- 1 508 508 25 Jul 5 10:08 /home/tuser1/.bash_history 262146 4 -rw-r--r-- 1 508 508 124 May 11 07:21 /home/tuser1/.bashrc 262147 4 -rw-r--r-- 1 508 508 18 May 11 07:21 /home/tuser1/.bash_logout 262149 0 -rw-rw-r-- 1 508 508 0 Jul 5 10:08 /home/tuser1/abc.txt 1049732 0 -rw-rw---- 1 508 mail 0 Jul 5 10:08 /var/spool/mail/tuser1
13、查找/etc目錄下所有用戶都有寫權限的文件；
# find /etc -perm -222 -ls 實例演示 find /etc -perm -222 -ls 524956 0 lrwxrwxrwx 1 root root 15 Jun 27 23:21 /etc/rc.sysinit -> rc.d/rc.sysinit 524545 0 lrwxrwxrwx 1 root root 30 Jun 27 22:59 /etc/fonts/conf.d/40-nonlatin.conf -> ../conf.avail/40-nonlatin.conf 524552 0 lrwxrwxrwx 1 root root 30 Jun 27 22:59 /etc/fonts/conf.d/65-nonlatin.conf -> ../conf.avail/65-nonlatin.conf
14、查找/etc目錄下大于1M，且類型為普通文件的所有文件；
# find /etc -type f -size +1M -exec ls -lh {} \;
實例演示
[root@C664BSLab ~]# find /etc -type f -size +1M -exec ls -lh {} \;
-rw-r--r--. 1 root root 8.1M Jun 27 23:22 /etc/selinux/targeted/modules/active/policy.kern
-rw-r--r--. 1 root root 8.1M Jun 27 23:22 /etc/selinux/targeted/policy/policy.24
15、查找/etc/init.d/目錄下，所有用戶都有執行權限，且其它用戶有寫權限的文件；
# find /etc/init.d -perm -113 -ls 實例演示 [root@C664BSLab ~]# find /etc/init.d -perm -113 -ls 526070 0 lrwxrwxrwx 1 root root 11 Jun 27 23:20 /etc/init.d -> rc.d/init.d
16、查找/usr目錄下不屬于root、bin或hadoop的文件；
# find /usr -not \( -user root -o -user bin -o -user hadoop \) -ls 實例演示 [root@C664BSLab ~]# find /usr -not \( -user root -o -user bin -o -user hadoop \) -ls 2628995 12 -rwsr-xr-x 1 abrt abrt 10296 May 12 04:43 /usr/libexec/abrt-action-install-debuginfo-to-abrt-cache
17、查找/etc/目錄下至少有一類用戶沒有寫權限的文件；
# find /etc -not -perm -222 -ls 實例演示 [root@C664BSLab ~]# find /etc -not -perm -222 -ls 524289 12 drwxr-xr-x 105 root root 12288 Jul 5 10:08 /etc 525293 4 drwxr-xr-x 2 root root 4096 Jun 27 23:21 /etc/postfix 525306 8 -rw-r--r-- 1 root root 5113 Nov 10 2015 /etc/postfix/master.cf 525302 12 -rw-r--r-- 1 root root 9904 Nov 10 2015 /etc/postfix/generic 525309 16 -rw-r--r-- 1 root root 12494 Nov 10 2015 /etc/postfix/virtual
18、查找/etc目錄下最近一周內其內容被修改過，且不屬于root或hadoop的文件；
# find /etc -mtime -7 -a -not \( -user root -o -user hadoop \) -ls 實例演示 [root@C664BSLab ~]# find /etc -mtime -7 -a -not \( -user root -o -user hadoop \) -ls 525528 0 -rw-r--r-- 1 user1 user1 0 Jul 5 10:53 /etc/abc.txt
原創文章，作者：N20-背旅，如若轉載，請注明出處：http://www.www58058.com/23433
寫的很好，排版也很棒，加油