Linux

1. comm [1 2 3] file1 file2It is very convenient to compare two sequential files to compare data.Actual use:Verify the current network data to see if it is accurate. For example, to compare data in the database and shared memory data, is consistent,

Today learned the first day of the course, understand the history of Linux, the system core operating mode, more thorough understanding of the underlying work mode. Listen to the outline of the Marco, more and more looking forward to the course, it

1) Tool DescriptionIn SSH login software such as SECURECRT, it is quite convenient to upload/download files by entering the Rz/sz command in the Linux interface, if it is not installed on your Linux system, it can be installed manually.SZ command:

Learning Order:One, at least familiar with an embedded chip architectureThe most suitable for beginners is the arm chipSecond, the use and transplant of ubootFirst of all, to understand the uboot start-up process, according to the boot sequence,

1. The new opening times the wrong e:dpkg is interrupted, you must manually run sudo dpkg--configure-a to resolve this issueSolution: http://forum.ubuntu.org.cn/viewtopic.php?t=386943The file in the ##/var/lib/dpkg/updates folder has a problem

When the file path contains Chinese, you can enter a partial file name, and then press the TAB key. When the path contains Chinese brackets, use a slash, such as: \ (..., \).You can also use Ls-li to view the Inum (inode number) and then access it

See two macro functions when looking at the code: likely () unlikely ()#define LIKELY (x) __builtin_expect (!! (x), 1) #define unlikely (x) __builtin_expect (!! (x), 0)__builtin_expect () is about processing branch predictions, allowing the compiler

My Linux, I'm the boss of my acquaintance with LinuxIn July this year, our school began to let us intern, find their own internship units. Before this teacher also took us to Beijing free training for half a month of programming, because this is not

I recently learned Linux, want to clone more than one CentOS to practice installing software under Linux, configure the environment. Because the system is not very familiar with, want to maintain a pure version, if the system play bad, delete and

Assume that a Linux system has a file called "-test". If the user wants to delete it and, following the general removal method, enter the "rm-test" command on the command line, the interface prompts for "invalid Options" (invalid option). The reason

1 First click VM--install vmware Tools(There will be a hint below the virtual machine to get you to mount VMware tools into CDROM. VMware has loaded a virtual CD-ROM with a Linux ISO image tool in the mirror)2 Linux execution commands into the

ULIMIT-A displays various restrictions for the current user.The numeric value of ULIMIT-N indicates the number of files each process can open.In general, the value of Ulimit-n is 1024.When the number of files opened by a process exceeds this limit,

A few days ago in windows8.1 installed ubuntu14.04, in the Windows deep sleep, open and enter the option to enter the system, then did not pay attention, chose to enter the Linux system, but entered one after the discovery can not enter the Windows

Red Hat/CentOSext4 cannot format large partitions The RedHat/CentOS 6.5 e2fsprogs version is earlier than 1.41.12, so you cannot create a file system larger than 16 TB. Download the latest e2fsprogs, compile and install

Linux boot process details For any system, it is not just a matter of power-on, but many things will happen in a few or dozens of seconds, understanding this complete process will be a prerequisite for solving any boot problems or improving the boot

Grub2 manual boot ubuntu Testing Machine OS: ubuntu 14.04.1 LTS x86_64 Disk Partitions: Filesystem 1K-blocks Used Available Use % Mounted on/Dev/sda1 19736236 3676896 15033756 20%/None 4 0 4 0%/sys/fs/cgroupUdev 369132 4 369128 1%/devTmpfs 75984 8

CentOS7 change target (running level) 1. Use commands to switch the running level/Target # Systemctl isolate multi-user.target // switch to run level 3, this command has no effect on the next start, equivalent to telinit 3 # Systemctl isolate

How to view and modify file permissions in CentOS View permission commandsYou can use the ls-lD command to view the related permissions of the Directory, or directly use ls-la For example Ls-l www.jb51.net // This indicates viewing the

Common port 80, 22, and 3306 operations for CentOS #/Sbin/iptables-I INPUT-p tcp -- dport 80-j ACCEPT#/Sbin/iptables-I INPUT-p tcp -- dport 22-j ACCEPT #/Sbin/iptables-I INPUT-p tcp -- dport 3306-j ACCEPT Then save: #/Etc/rc. d/init. d/iptables

CentOS sets Nic boot automatic start, configuration and other ifcfg-eth0 Step 1 configure the file in/etc/sysconfig/network-scripts/ifcfg-eth0. Ifcfg-eth0 configuration details under CentOS6.4: [Root @ Jeffery] #