Linux OPS Practice-January 19, 2016-February 3 course Assignments

1, describe the CENTOS6 system boot process;

1) Load the hardware information of the BIOS and self-test, and obtain the first bootable device according to the configuration;

2) Read and run the boot Loader (grub, Spfdisk, etc.) of the MBR in the first boot device;

3) According to the configuration of boot loader loading Kernel, Kernel will start to detect hardware and load drivers;

4) After the hardware driver is successful, Kernel will actively call the INIT program, and Init will get run-level level;

5) Init runs the/etc/rc.d/rc.sysinit file to prepare the operating environment (e.g. network, time zone, etc.) for the software to run;

6) Init runs the various services under Run-level to enable it (script mode);

7) Init run/etc/rc.d/rc.local file;

8) Init run Terminal simulation program Mingetty to start the login program, and finally wait for users to log on;

2, Description/etc/rc.d/rc.sysinit script function;

1) Access to network environment and host information:

Read the network configuration file/etc/sysconfig/network, get the host name and default gateway and other network environment.

2) test and Mount memory device/proc and U disk device/sys:

In addition to mounting the memory device/proc, it also proactively detects if there is a USB device on the system, and if so, it actively loads the USB driver and attempts to mount the USB file system.

3) Decide whether to start SELinux:

4) Start the system random number generator

5) Configure the terminal font:

6) Configure the Welcome information displayed during the startup process;

7) Configure the system time (clock) and time zone configuration: Read-in/etc/sysconfig/clock configuration values

8) Detection of peripheral devices and testing of Plug and Play (PnP) Parameters:

The detection of peripheral devices, such as IDE/SCSI/network/sound effects, and the use of core modules loaded to test the PnP device, are initiated based on the core's detection at startup (/proc/sys/kernel/modprobe).

9) Loading of user-defined modules

The user can add a custom module to the/etc/sysconfig/modules/*.modules and it will be loaded into the system at this time

10) Load the relevant configuration of the core:

The system will take the initiative to read the configuration value of the/etc/sysctl.conf file.

11) Configure host name and initialize Power Management module (ACPI)

12) Initialize the software disk array: mainly through the/etc/mdadm.conf to configure the good.

13) Initialize the file system function of LVM

14) Check disk File system with Fsck: FileSystem check

15) Conversion of disk quota quota (not necessary):

16) Re-mount the system disk in writable mode:

17) Start Quota function: So we do not need to customize the Quotaon action

18) Start the system virtual random number generator (pseudo-random):

19) Clear the cache file during startup:

20) Launch relevant information to load the/VAR/LOG/DMESG file.

3. Summarize the usage of the Text Processing tool sed and awk (must accompany the example)

1) SED

①sed using formats and options

[[Email protected] ~]# [OPTION] ' n1,n2]fun ' [input-file]

OPTION

-N: Use Quiet (silent) mode. In the usage of general sed, all from STDIN

Data is generally listed on the screen. However, if you add the-n parameter, only the

The line (or action) in which the SED is specially processed is listed.

-E: Action editing of SED directly in command-line mode;

-F: Writes the action of SED directly in a file, the-f filename can be run in filename

SED action;

-r:sed's actions support the syntax of extended formal notation. (The default is the basic formal French notation)

-I: Directly modifies the contents of the read file, not the screen output.

N1, N2: Not necessarily exist, usually represents "the number of rows selected for action", for example, if my action

is required between 10 and 20 rows, then "10,20[Action Behavior"

Fun

A: New, a can be followed by a string, and these strings will appear on a new line (the next line)

C: Replace, C can be followed by a string, these strings can replace the line between N1,N2

D: Delete, because is deleted, so d is usually not followed by any string;

I: Insert, I can be followed by the string, and these strings will appear on a new line (the current line);

P: Print, that is, print out a selected data. Normally p will run with the parameter Sed-n ~

S: Replace, can be directly replaced by work! Usually this s action can be paired with formal notation!

For example 1,20s/old/new/g is!

② Instances

            [[email protected] ~]#  cat sed   //edited files              1            2             3            4             [[email protected] ~]#  sed  ' 3ad '  sed    //adds a string after a specified range              1            2             3             d            4             [[email protected] ~]# sed  ' 3d '  sed   //Delete a specified range of rows             1             2             4            [[email  protected] ~]# sed  ' 2,3cno '  sed  //replaces the behavior of the specified range no             1             no            4             [[email protected] ~]# sed  ' 3iok '  sed   //Insert ok            1   before line 3rd            2            ok             3             4            [ [email protected] ~]# sed -n  ' 2,3p '  sed     // Output selected text in silence             2             3             [[email protected] ~]# sed  ' 1,4s/3/ok/g '  sed   //replace 3 with OK             1             2             ok             4 

4, write a script, generate 10 random numbers, and according to the order from small to large (requires at least 2 Chinese law);

5. Execute the script/data/get_username.sh at 1:5 A.M. every Tuesday and output the script to the/tmp/get_username.log log file;

6. Write a script: If a path does not exist, it is created as a directory, otherwise it is present, and the content type is displayed;

7, write a script, print 9x9 multiplication table;

8, describe the work flow of DNS, as well as a complete set of DNS master-slave server, the relevant domain name and IP can be set by itself.

Linux OPS Practice-January 19, 2016-February 3 course Assignments