Linux

VM Virtual machines use ubuntu16.04 to learn.I. BASIC commands1.cat commandCat usage: 1.cat filename (open file)2.cat filename1 filename2 >filename3 (add filename1 filename2 content after filename3 original purge)or cat filename1 filename2

The Chkconfig command is primarily used to update (start or stop) and query run-level information for system services. Keep in mind that Chkconfig does not immediately automatically disable or activate a service, it simply changes the symbolic

Explain the output of the free command on Linux.Here is the result of the free run, with a total of 4 rows. For convenience, I added a column number. This can be seen as a two-dimensional array fo (free output). For example: FO[2][1] = 24677

System settingsDefault output device: Standard output, STDOUT, 1Default input device: standard input, STDIN, 0Standard error Output: STDERR, 2Standard input: KeyboardStandard output and Error output: DisplayI/O redirection:Linux:: Overwrite

In bash, variables are categorizedClassification according to the effective scope1. Local variables: Valid only in this shell, not valid for other shells2. Environment variable: Valid only in the current shell and its child shell. Invalid for other

Special permissions: Suid,sgid,stickySecurity context:1. The process runs as a user, and the process is the agent that initiates the user of this process, so all operations are done with this user's identity and permissions;2. Permissions matching:(1

Ideas for dealing with Linux system failures:1. Pay attention to the error message.2. Review the log file. Message (System log) service log error (Application log)3. Analysis, positioning problems.4. Solve the problem.Forgot root password?Reset:

Disk partitioning is actually changing the contents of the Dpt-Disk partition table (64Bytes, 16 bytes per partition table). linux fdisk  Interactive partition test (note that the primary partition must not exceed 4-disk requirements, the extended

I. Download the SBT installation packageFrom the SBT website: http://www.scala-sbt.org/download.html Download the installation package, take sbt-0.13.13.tgz as an example.Second, installation1. Move the downloaded binary package to the/usr/local

CD directory name switch to a directory CD: Up-level directory CD/root directory ll list the files under the folder Ifconfig Get IP PWD current Directory mkdir Directory name creation directory RM-RF file name or directory name

[[Email protected] Desktop]# ifconfigEno16777736:flags=4163 MTU 1500inet 192.168.1.96 netmask 255.255.255.0 broadcast 192.168.1.255Inet6 fe80::20c:29ff:fe1e:84b5 Prefixlen ScopeID 0x20Ether 00:0c:29:1e:84:b5 Txqueuelen (Ethernet)RX packets 2148

Security context: Whether the user's uid/gid is in the owner/owner group of the file;User (UID)/group (GID): identifierProcesses and files corresponding to user/group;User Group Category:Private group: A group that has the same name as the user name

What does the CPU information in the top command of Linux mean?Cpu (s): 62.1% us, 15.9% sy,0.1% ni, 19.4% id,2.0% wa,0.1% hi,0.4% simem:8247956k total,8232004k used,15952k free,205240k buffersswap:8191992k total,48k used,8191944k free,7156092k

Sockets need to be bundled on the address to be useful!Identify the target process to have 1. The other computer's computer network address IP 2. Port number shows the specific process of the other machineThe sequence of bytes is the meaning of the

Use the ssh public key to automatically log on to the linux server, sshlinux As a linux administrator, logging on to multiple Linux servers for remote operations is part of daily work. However, as the number of servers increases, the system will

Install RabbitMQ in CentOSGossip Zookeeper this article describes how to install RabbitMQ in the CentOS operating system.Erlang Download Erlang:Erlang-18.1-1.el7.centos.x86_64.rpm Install Erlang: rpm -ivh

Modify the default running level of CentOS7 The CentOS system has seven runlevels)Running level 0: The system is down. The default running level cannot be set to 0. Otherwise, the system cannot start normally.Running Level 1: single-user working

Command operations that must be understood in LinuxGuideFiles are an important concept in linux. In Linux, everything (almost everything) is a file. Simply put, the basic printf () and scanf () functions in C are actually file operations. Although

Ls command detailsGuideOne common task for Linux users is to list the contents of directories on the command line. We already know that ls and dir are two Linux commands available to list the contents of directories, the former is more popular, and

How can we build a cloud O & M platform with high performance?GuideAfter the standardization implementation, we will gradually implement some tools and automation as the number increases or the number of O & M scenarios increases. At this stage, our