linux practice test

Linux users, user groups, and file permissions [command practice] linux permission system consists of users, user groups, and permissions. For theoretical aspects, you can refer to another article: linux to view all users and all user groups [theory] http://www.bkjia.com/ OS /201304/205743.html users are one by one log

right knife and fork if (Semop (Semid, sops, 1) = =-1) err_exit ("Wait_2fork error");} *///release two cutlery void signal_2fork (unsigned short) {unsigned short left = no; unsigned short right = (no+1)%5; struct SEMBUF sops[2] = {{left, 1, 0}, {right, 1, 0}}; if (Semop (Semid, SOPs, 2) = =-1) err_exit ("Signal_2fork error");} philosopher void philosopher (Unsigned Short No) {Srand (Time (NULL)); while (true) {cout int main () { //Creates a semaphore set: Contains 5 semaphore

the things are compressed separately. If you compress the folder, do not add this is not compressed. will display xx is a directory--ignored)-V displays materials such as the name and compression ratio of the file being compressed.-T verifies the integrity of the compressed file.-1 The fastest compression, compression ratio is very low,-9 The best compression, compression ratio is very high, but the rate is very slow. (You can specify a number 1~9, which is 6 levels by default)The gunzip has no

Program hack for Linux PracticeThis time the practice is file hack, let's start with the login executable file! First we execute this executable program① we want to be able to log in without knowing the password. And no matter what the password is, it is prompt "on your command,my master!" ".The program is first disassembled.We'll first find the entrance to the main function. We can see the CMP statement, t

return value.3.shell variable Quantum string knowledge650) this.width=650; "Width=" 720 "height=" 305 "title=" 1.png "style=" width:720px;height:305px; "alt=" Wkiol1j4d1jcztx-aafomugkd9o187.png "src=" https://s5.51cto.com/wyfs02/M01/91/B9/ Wkiol1j4d1jcztx-aafomugkd9o187.png "border=" 0 "vspace=" 0 "hspace=" 0 "/>Tips:The colon of the expression in the above ID 11-14 can be omitted, and if the colon is omitted, the "empty or Unassigned" section in each definition is changed to "Unassigned".For e

[Practice OK] in Linux, check the context of environment variables when the process (program) is started. because of the recent installation of jira In Linux, a Chinese plug-in is installed. once it is set to start, it is in English, and after the terminal restarts again, it seems that the plug-in takes effect, and it is restored to normal Chinese... [

is This is-F oldboyfile #删除原始文件 is actually a hard link to delete a fileClearer: This is oldboyfile Hint: Strange, the content is still in, actually this is because has the oldboyfile_hard_link hard link existence, therefore even if deletes the oldboyfile, but still has the hard link to the file Inode node, therefore, At this point the file will not be released and deleted, and when the file Oldboyfile is deleted, only the connection oldboyfile to the Inode node of the file is deleted. [em

LINUX practices and discussions on embedded systems-general Linux technology-Linux programming and kernel information. The following is a detailed description. 1. Practical Purpose Porting the KERNEL of KERNEL 2.6 to a mature embedded hardware platform; In order to practice the initial development requirements of an e

Article title: Xen virtual machine practice: how to create a snapshot using Linux commands. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source. A vm snapshot is a good function that ca

]# chkconfig nginx onStart:[[Email protected] lib64]# service Nginx startStarting nginx: [OK] 8. Start error Handling [[Email protected] init.d]# service Nginx startStarting Nginx:/usr/local/nginx/sbin/nginx:error while loading shared libraries:libpcre.so.1:cannot open Shared object File:no such file or directory[FAILED]Using LDD to see the dynamic function libraries contained in Nginx[[email protected] src]# LDD $ (Which/usr/local/nginx/sbin/nginx)

Tags: soft connect http RIP network different shortcuts boot automatically mount link charactersFirst, the boot automatically mount file system settings Create a new Rhel directory under/media and mount the/DEV/SR1 second optical drive to that directory #mkdir/media/rhel#mount/dev/sr1/media/rhel Automatically mount file system settings on boot /DEV/SR1 boot automatically mounts to/media/rhel by modifying the file Mount table/etc/fstabRestart the computer: #init 6, and

patiently ...). ）3) Unzip the installation package and copy the files to the/opt/dotnet directory4) Create a soft link file named dotnet in the/usr/local/bin directory to point to the/opt/dotnet/dotnet file, and the soft link is understood as a shortcut2. Create a. Net Core applicationmkdir HwappCD Hwappdotnet NewCommand Simple explanation1) Create a directory named Hwapp2) Enter the directory3) Execute the dotnet new command to create a. Net Core project3. Restore dependent libraries Run prog

need to add a $ symbol here, the same as a, B.Pls Input One Num:2[Email protected] ~]# read-t 5-p "Pls input" num: "a BPls Input 2 Num:1 Above for I read "with the old boy learn Linux Yun Koriyuki Shell programming Combat" This book when the note, if there are any copyright issues, please contact the message.This article is from the "shayatou_1990" blog, make sure to keep this source http://shayatou1990.blog.51cto.com/12806916/1918020"Learn

; /* Buffer for Ipc_stat, Ipc_set */ unsigned short *array; /* Array for GETALL, SETALL */ struct seminfo *__buf; /* Buffer for Ipc_info (linux-specific) */};Practice: setvalunion mysemun{ int val; Value for setval// struct semid_ds *buf; Buffer for Ipc_stat, ipc_set// unsigned short *array; Array for GETALL, setall// st

The test command is a tool for testing conditional expressions in the shell for conditional judgments.GrammarTest (option)if [(option)]File test-b-c-s-p-f-d-e-g-o-g-u-k-r-w-x-sInteger test-eq (equal): Tests whether two integers are equal;-ne (Not equal): Tests whether two integers are unequal;-GT (great than): test whe

group is readable, other users are unreadable and not writable, with the number set9. For Book.txt Read permissions to EveryoneTask four: Complete the following actions as required and record the process on the internship report1. Copy the/etc/man.config to/think, compress/think/man.config to Good.tar, and under/think/newBuild file bad.conf, Man.config, bad.conf simultaneously compressed to Ftpp.tar2. Displays the contents of the Ftpp.tar, creates a new file Top.txt, appends it to Ftpp.tar3. Un

Linux practice engineer study Note 3: file system maintenance-general Linux technology-Linux technology and application information. The following is a detailed description. Original Author: junger Ext2/ext3 store files through data blocks Format a file system: Mkfs. ext3? B 4096? I 8192? M 5/dev/sdb4 -B data block

1. Framebuffer application Programming(1) Open the device file(2) Obtaining device informationMacro-defined commands in/linux/fb.hImmutable information Fscreeninfo, using the IOCTL parameter has a Fbioget_fscreeninfo macro name, indicating the use of the IOCTL from the driver to obtain the unchanging information of the LCD deviceVariable information vscreeninfo, using the IOCTL parameter with the Fbioget_vscreeninfo macro name, indicates that the vari

>/proc/sys/net/ipv4/conf/all/arp_ignore[[emailprotected]~]#echo2>/ proc/sys/net/ipv4/conf/lo/arp_announce[[emailprotected]~]#echo2>/proc/sys/net/ipv4/ Conf/all/arp_announcers1:10.9.9.2[[emailprotected]~]#ipaddr10.9.9.8/32dev lo[[emailprotected]~]#iprouteadd10.9.9.8devlo[[email protected]~]#echo1>/proc/sys/net/ipv4/conf/lo/arp_ignore[[emailprotected] ~]#echo1>/proc/sys/net/ipv4/conf/all/arp_ignore[[emailprotected]~]#echo 2>/proc/sys/net/ipv4/conf/lo/arp_announce[[emailprotected]~]#echo2>/proc/ Sy

. (Can not connect, not because of network problems, the host and virtual machine is the same network segment, do not need to be networked or log on) 　　　　 With respect to certificates, this problem may occur when the client generates a public private key pair, and the public key is written to the virtual machine: Guess this is a key file, and the files here are impossible to write. Can try to use sudo permissions, do not know, do not solve this problem, repla