马哥教育网络班20期+第5周课程练习

1、显示/boot/grub/grub.conf中以至少一个空白字符开头的行

[root@cloud ~]# grep -P '^\s+\S' /boot/grub/grub.conf 
root (hd0,0)
kernel /vmlinuz-2.6.32-358.el6.i686 ro root=/dev/mapper/vg_cloud-lv_root rd_NO_LUKS rd_NO_MD rd_LVM_LV=vg_cloud/lv_swap crashkernel=auto.UTF-8 rd_LVM_LV=vg_cloud/lv_root  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
initrd /initramfs-2.6.32-358.el6.i686.img

2、显示/etc/rc.d/rc.sysinit文件中以#开头，后面跟至少一个空白字符，而后又有至少一个非空白字符的行；

[root@cloud ~]# grep -P '^#\s+\S+' /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.
# Initialize hardware
# Set default affinity
# Load other user-defined modules
# Load modules (for backward compatibility with VARs)
# Configure kernel parameters
# Set the hostname.
# Sync waiting for storage.
# Device mapper & related initialization
# Start any MD RAID arrays that haven't been started yet
# Remount the root filesystem read-write.
# Clean up SELinux labels
# If relabeling, relabel mount points.
# Mount all other filesystems (except for NFS and /proc, which is already
# mounted). Contrary to standard usage,
# filesystems are NOT unmounted in single user mode.
# The 'no' applies to all listed filesystem types. See mount(8).
# Update quotas if necessary
# Check to see if a full relabel is needed
# Initialize pseudo-random number generator
# Configure machine if necessary.
# Clean out /.
# Do we need (w|u)tmpx files? We don't set them up, but the sysadmin might...
# Clean up /var.
# Clean up utmp/wtmp
# Clean up various /tmp bits
# Make ICE directory
# Start up swapping.
# Set up binfmt_misc
# Boot time profiles. Yes, this should be somewhere else.
# Now that we have all of our basic modules loaded and the kernel going,
# let's dump the syslog ring somewhere so we can find it later
# create the crash indicator flag to warn on crashes, offer fsck with timeout
# Let rhgb know that we're leaving rc.sysinit

3、打出netstat-tan命令执行结果中以‘LISTEN’，后或跟空白字符结尾的行；

[root@cloud ~]# netstat -tan | grep -P 'LISTEN\s*$'
tcp        0      0 0.0.0.0:5902                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:111                 0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:8880                0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:6002                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 0.0.0.0:12346               0.0.0.0:*                   LISTEN      
tcp        0      0 127.0.0.1:25151             0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:63009               0.0.0.0:*                   LISTEN      
tcp        0      0 0.0.0.0:8388                0.0.0.0:*                   LISTEN      
tcp        0      0 :::111                      :::*                        LISTEN      
tcp        0      0 :::80                       :::*                        LISTEN      
tcp        0      0 :::14513                    :::*                        LISTEN      
tcp        0      0 :::6002                     :::*                        LISTEN      
tcp        0      0 :::22                       :::*                        LISTEN      
tcp        0      0 ::1:631                     :::*                        LISTEN      
tcp        0      0 ::1:25                      :::*                        LISTEN      
tcp        0      0 :::443                      :::*                        LISTEN

4、添加用户bash, testbash, basher, nologin (此一个用户的shell为/sbin/nologin)，而后找出当前系统上其用户名和默认shell相同的用户的信息；

[root@cloud ~]# for u in bash testbash basher nologin; do
> [ "$u" = "nologin" ] && shell=/sbin/nologin || shell=/bin/bash 
> useradd -s $shell $u
> done
[root@cloud ~]# egrep --color '^([^:]*):.*\1$' /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、显示当前系统上root、fedora或user1用户的默认shell；

[root@cloud ~]# grep -P '^(?:root|fedora|user1)' /etc/passwd | grep -oP '[^:]*$'
/bin/bash
/bin/bash
/bin/bash

6、找出/etc/rc.d/init.d/functions文件中某单词后面跟一组小括号的行，形如：hello()；

[root@cloud ~]# grep -P '\w+\(\)' /etc/rc.d/init.d/functions 
fstab_decode_str() {
checkpid() {
__readlink() {
__fgrep() {
__umount_loop() {
__umount_loopback_loop() {
__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() {
strstr() {
confirm() {
get_numeric_dev() {
is_ignored_file() {
is_true() {
is_false() {
apply_sysctl() {
key_is_random() {
find_crypto_mount_point() {
init_crypto() {

7、使用echo命令输出一个绝对路径，使用grep取出其基名；扩展：取出其路径名

[root@cloud ~]# echo /path/to/file | grep -o '[^/]*$'
file
[root@cloud ~]# echo /path/to/file | grep -oP '^.*(?=/)'
/path/to

8、找出ifconfig命令结果中的1-255之间数字；

[root@cloud ~]# ifconfig | egrep -o '\b[1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]\b'
127
1
255
1
128
164

9、挑战题：写一个模式，能匹配合理的IP地址；

[root@host1 ~]# ifconfig | egrep -o '(\b([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}\b([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\b'
192.168.124.71
192.168.124.255

10、挑战题：写一个模式，能匹配出所有的邮件地址；

[root@host1 ~]# cat <<EOF | grep -oP '\b[-\w]+@([\w-]+\.){1,}[a-zA-Z]{2,3}\b'
> right email:
> <tom@163.com>
> bbs: sys-admin@126.cn end
> >jack@sina.com.cn!
> wrong email:
> hahhafs@@alsd@@
> asdfa.@sasda.com
> asdafs@..com
> adaf@.cn
> EOF
tom@163.com
sys-admin@126.cn
jack@sina.com.cn

11、查找/var目录下属主为root，且属组为mail的所有文件或目录；

[root@host1 ~]# find /var -user root -a -group mail
/var/spool/mail

12、查找当前系统上没有属主或属组的文件；进一步：查找当前系统上没有属主或属组，且最近3天内曾被访问过的文件或目录；

[root@host1 ~]# find `ls -d /* | egrep -v '/proc|/sys'` -type f \( -nouser -o -nogroup \) -ls
   132    4 -rw-r--r--   1 1005     distro         18 11月 20  2015 /home/mandriva/.bash_logout
   133    4 -rw-r--r--   1 1005     distro        193 11月 20  2015 /home/mandriva/.bash_profile
   134    4 -rw-r--r--   1 1005     distro        231 11月 20  2015 /home/mandriva/.bashrc
135229525    0 -rw-rw----   1 1005     mail            0 6月 29 17:34 /var/spool/mail/mandriva

[root@host1 ~]# find `ls -d /* | egrep -v '/proc|/sys'` \( -nouser -o -nogroup \) -a -atime -3 -ls
   131    0 drwx------   2 1005     distro         59 6月 29 17:34 /home/mandriva

13、查找/etc目录下所有用户都有写权限的文件；

[root@host1 ~]# touch /etc/allwrite.txt && chmod 777 /etc/allwrite.txt
[root@host1 ~]# find /etc -type f -perm -0222 -ls
134664121    0 -rwxrwxrwx   1 root     root            0 7月  9 12:39 /etc/allwrite.txt

14、查找/etc目录下大于1M，且类型为普通文件的所有文件；

[root@host1 ~]# find /etc -type f -size +1M -ls
67526230 6824 -r--r--r--   1 root     root      6984832 7月  7 23:02 /etc/udev/hwdb.bin
202247550 3772 -rw-r--r--   1 root     root      3858924 11月 21  2015 /etc/selinux/targeted/policy/policy.29

15、查找/etc/init.d/目录下，所有用户都有执行权限，且其它用户有写权限的文件；

[root@host1 ~]# find /etc -type f -perm -0113 -ls
134664121    0 -rwxrwxrwx   1 root     root            0 7月  9 12:39 /etc/allwrite.txt

16、查找/usr目录下不属于root、bin或hadoop的文件；

[root@host1 ~]# find /usr -type f ! \( -user root -o -user bin -o -user hadoop \) -ls
202649998   16 -rwsr-sr-x   1 abrt     abrt        15336 12月  1  2015 /usr/libexec/abrt-action-install-debuginfo-to-abrt-cache

17、查找/etc/目录下至少有一类用户没有写权限的文件；

[root@host1 ~]# find /etc -type f ! -perm -0222 -ls

18、查找/etc目录下最近一周内其内容被修改过，且不属于root或hadoop的文件；

[root@host1 ~]# touch /etc/hello.txt
[root@host1 ~]# chown abrt /etc/hello.txt
[root@host1 ~]# find /etc -type f ! \( -user root -o -user hadoop \) -mtime -7 -ls
134664122    0 -rw-r--r--   1 abrt     root            0 7月  9 12:50 /etc/hello.txt

原创文章，作者：gateray，如若转载，请注明出处：http://www.178linux.com/23272