Linux

Telnet 192.168.1.245 3306Use the script above to test whether the port is open, and note that the service that is enabled for the terminal must be turned on.If it is not open,Vi/etc/sysconfig/iptables-A rh-firewall-1-input-m state--state new-m tcp-p

Representative character Permissions Meaning to the file Meaning to the directory R Read permissions Allow viewing of file contents Allow listing content in directory W Write

I. Creating and deleting CatalogsCommand: mkdirSyntax: mkdir [-MP] [directory name]Example: Mkdir-p ~/1/2/3650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M01/71/60/wKiom1XMfQXygdCEAACJFs5J8gM305.jpg "title=" 1.png " alt=

1. Production of embedded Linux kernel (the linux-ok6410 kernel that is used here, with kernel configuration file config-file)A. Go to the kernel directory to clear the original configuration and intermediate files:Make cleanB. Configure the

Gzip is the command used for compression on LinuxThere is a parameter for num -num Adjusts the speed of compression with the specified number num,-1 or--fast represents the fastest compression method (low compression ratio), 9 or--best represents

1, atomic operation, is the basis of other synchronization methods.2, Spin lock, the thread tries to acquire a spin lock that has been held by someone else, the current thread is busy waiting, consuming CPU resources.3, read and write spin lock,

$ ((expression))echo $ (wrong): echo $ ((+)): Right Echo Front-{a,b,c}-back Front-a-back Front-b-back Front-c-back Echo Start{1..5}endStart1end start2end start3end start4end start5end Echo Start{a. Z}end $ (cmd) Command replaces the output of one

QuotaFor WWW server, for example: the capacity limit for everyone's web space!For mail server, for example: The message space limit for everyone.For file server, for example: Maximum available network hard disk space for everyone (most common in a

Run levelinit 6 = = REBOOT = = Shutdwon-r now restartinit 0 = = Shutdown-h now offSingle-User modePress any key---> Press E to edit the 2nd item in three seconds after startup and press E---press 1--> at the end and press B to start-up in a few

Linux Desktop Environment IntroductionCompared to the current Windows system, Unix/linux itself is not a graphical interface, we usually see on the unix/linux distribution of the graphical interface is actually just run on the Linux system on a set

1. Cat command:function:1) Displays the entire file.Example: $ cat FileName2) Connect the file string to the basic output, such as merging several files into one file or output to the screen.Example: $ cat file1 file2 > fileDescription: Connect the

Grub-->kernel-->initrd-->rootfs (/sbin/init,/bin/bash)Build a simple Linux system on a new hard drive, with/sbin/init initialization and the ability to use/bin/bash1. Disk partitioning: Create boot partition only mount to/mnt/boot and root partition

LocateNon-real-time, non-accurate lookups are based on a system-wide file databaseThe advantage is that speed is fastDatabase can be updated immediately using UpdateDBFindReal-time precision, support multi-search criteria, use traversal files to

Linux in-depth Chapter four: construction of nginx+tomcat dynamic and static separation architectureThe static and dynamic separation of nginx is simply to separate dynamically and statically, not only to physically separate dynamic pages from

Applicable system: Linux (Redhat, Centos,debian,ubuntu)* The Linux cloud Server data disk is not partitioned and formatted, and can be partitioned and formatted according to the following steps.The following operation will divide the data disk into

How Linux modifies file permissionsBefore modifying the file permissions, you need to understand the permissions of the "rwx" and the corresponding relationship between the numbers, where r=4,w=2,x=1.For example: "Drwxr-xr-x", the first "D" is the

If I say that if, in one of your directories, you will often generate some junk files, such as access logs, error logs, core files, and you do not want to take a few minutes to manually check, then you can use scheduled tasks to solve the way. There

SOURCE Command usage:SOURCE FileNameFunction: Reads and executes the commands in the filename under the current bash environment.Note: This command usually uses the command "." To replace.such as: source. BASH_RC and. The. BASH_RC is equivalent (it

Linux Boot Sequence1. CPU InitializationThe CPU itself initializes, takes instructions from a fixed location (0XFFFFFFF0) and executes, which is a jump instruction and jumps to the header of the BIOS code.2. Load the BIOSThe BIOS is cured in a ROM

Reasons to use multithreading 1:One of the reasons to use multithreading is that it is a very "frugal" multi-tasking approach compared to the process. WeKnow that under the Linux system, starting a new process must be assigned to its separate