linux practice test

The previous note mainly introduced the basic knowledge related to time_wait. This article describes how to solve the problem raised by the article title based on practice. 1. view the system network configuration and current TCP statusIt is necessary to understand the default network configuration of the system when locating and handling network problems in applications. Take the x86_64 Linux kernelversion

, named File2View the contents of the File1 file in a read-only mannerView The first 3 lines of the File1 fileView The following 2 lines of the File1 fileView the contents of the File1 file as a percentage of the pagePaging up and down to view the contents of the File1 fileCreate the following directory structuresh-3.2# tree/ftpserver//ftpserver/├──bin│ ├──register.py│ └──start.py├──conf│ └──settings.py├──core│ └──server.py├──db│ └──user.db├──lib│ └──common.py└──log└──access.log1: Switch t

:~/bashExport PATHName=user5Useruid= ' Id-u $NAME ' (useruid= ' grep "\Groupgid= ' Id-g $NAME ' (useruid= ' grep "\If [$USERUID-eq $USERGID]; Thenecho "The $NAME is good guy."Elseecho "The $NAME is bad guy."Fi4. Exercise: Write a scriptGiven a user, get their password warning period;And then determine whether the user password period is less than the warning period; Tip: The calculation method, the maximum period of use minus the number of days that have been used is the remaining period of use

, and then egrep find its path base name; Further use Egrep to remove its directory name (note that the directory name, not the directory path);MKDIR–P/DATA/PLTECHO/DATA/PLT | GREP-E-O "[^/]+$" first to indicate that the trailing slash end appears at least once:-E [^/]+$,-o indicates that only the matched string itself is displayed6. Find all files that are not root, bin or hadoop under the/usr directory;#find/usr-not-user root-a-not-userbin-a-not-user-hadoop#find/usr-not \ (-user root-o-user bi

Linux inter-process communication (IPC) Programming Practice (7) use of shared memory-System V shared memory (API) The system call mmap mentioned in the previous blog map a common file to implement shared memory. The System V shared memory described in this article is to map files in the shm of a special file System to implement shared memory communication between processes. That is to say, each shared memo

[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 a normal Chinese interface. Fir

Install SVN on linux and import it (personal practice) The original SVN server was deployed on windowsPC. As the leader requested, svn should be set up on the linux server and imported. Therefore, this operation is performed. First, you need to download the required package from the official website. My package is 1.6.16, and the maximum package is 1.9 ,: Http:/

" Accept for RecoverdirFilesystem in Use:ext4.imgUsing internal Journal at Inode 8Activ time After:sun June 7 22:43:54 2015Activ time Before:sun June 7 23:02:18 2015Inode 2 is allocatedUnknown code ext2 #0 for block bitmap for ext4.imgWarning:error-nr 2133571363 can not found file:/MAGIC-1: Start lost Directory searchMAGIC-2: Start lost File search--------Testdir/magic-2/image/jpeg/i_0000000012.jpg--------Testdir/magic-2/image/jpeg/i_0000000013.jpg--------Testdir/magic-2/image/jpeg/i_0000000014.

expire.99999 expiration time, 99,999 days to expire.7 How many days before your password expires:: Password disabled for Linux time/etc/groupshrek:x:501:If Todd is added to the group, it can be shrek:x:501:todd directly, other usersLinux users only differentiate between a UID of 0 and a UID of not 0./etc/gshadowRarely used.Tail-5/etc/passwd only see the last five lines of passwd.head-5/etc/passwd View passwd header Five elements file.Useradd-g root,b

Linux practice engineer study NOTE 4: Manage the disk file system-general Linux technology-Linux technology and application information. The following is a detailed description. Original Author: junger Mount device name mount point Mount/dev/fd0/mnt/floppy Optical Drive (IDE)/dev/cdrom (/dev/hdx) Optical Drive (SCSI)/

Practice C-linux general technology-Linux programming and kernel information in Linux. The following is a detailed description. In unbuntu linux, there is no direct compilation tool. C, java, and c ++ all need to download their own packages. Although this command is availabl

I want to practice PHP programs on Linux, environment configuration, which operating system is good? Some say with red hat, I used to own Ubuntu nothing, compile anything need C + + support, Dude, what kind of Linux do you recommend? Reply to discussion (solution) I'm using a centos5.5.Nothing has happened yet.I think this system is good. Debian centos6.

==skb->dev)) { if (pt_prev) {Inspired:1. The code above shows a delay in the processing of code skills, although deduction performance, but the implementation of the program to improve the complexity of code is not easy to read;2. Due to the needs of operating system optimization, the Linux implementation must contain many of the above-mentioned code optimization measures, as learners need to have a certain code simplification ability and thinkin

Basic principles and practice of Linux C programming (2018-06-16-19:12:15)Basic principles and practice of Linux C language programmingEfficient learning with Purpose: what to do and how to use itRe-knowledge of C language C language is a universal, process-oriented programming language, which is widely used i

parentheses line;# GREP-E-o "^[_[:alpha:]]+\ (\)"/etc/rc.d/init.d/functions5, use echo to output a path, and then egrep find its path base name; Further use Egrep to remove its directory name (note that the directory name, not the directory path);# echo "/etc/network" | Egrep-o "[^/]+?$"6. Find all files that are not root, bin or hadoop under the/usr directory;# find/usr-not \ (-user root-o-user bin-o-user hadoop \)7, one day the system was invaded, hackers in your system to leave the Trojan fi

As a wild programmer who left early as a master, the business can also reach the level of bluffing, but the rise to the performance level that is the mishap.Real pie in the sky, the company assigned a test performance task, really feel my sky stars are bright.High concurrency major limiting factors: CPU, network traffic, memory, system configurationCpuUsing top to see CPU utilization, press 1 to see how each CPU thread works; This shows the CPU idle,

Linux practice engineer study NOTE 2: Common commands for System Management-Linux general technology-Linux technology and application information. The following is a detailed description. Original Author: junger 1. useradd redhat 2. passwd redhat 3. su? 4. exit 5. df? H partition status 6. du? Sh/* si

Linux inter-process communication (IPC) Programming Practice (2) FIFO naming Pipeline In the previous article, we explained how to use anonymous pipelines to transmit data between processes, and also saw a defect in this method, these processes are started by a common ancestor process, which makes it inconvenient for us to exchange data between unrelated processes. Here, we will introduce another communicat

, blocking mode), if the length of the data being written is less than the waiting pipe_buf, either all bytes are written, or none of the bytes are written. If all of the write requests are destined for a blocking FIFO, and the data length of each write request is less than or equal to Pipe_buf bytes, the system ensures that the data will never be interleaved. (Refer to my previous blog post). Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reprodu

A way of communication between humans and computers.C language is suitable for Linux embedded. Gadgets.The Mac computer is the UNIX kernel.Second, the basic operation of Linux#vi A.C New File#rm A.C Delete FilesI current cursor before insertionA is inserted after the current cursorShift+a Line End InsertionShift+i Line Header Insertiono Insert Next lineShift+o the previous line insertsDD deletes the cursor