linux commands for hadoop administration

– Replacement--------------------------------------------------------------------------------------------------> REDIRECT output, overwrite the original content;>> redirect output, and additional functions;Example:CAT/ETC/PASSWD > A.txt Directing output to A.txtCAT/ETC/PASSWD >> a.txt Output and appendIfconfig > Ifconfig.txt--------------------------------------------------------------------------------------------------Pipelines are an important concept in

the specified usercd-: Switch back and forth between the previous directory and the current directoryLinux Command type:Built-in command: (shell) built-in which LSExternal command: An executable file corresponding to the command name on a path in the file system.Environment variables:What is a variable? A variable is a namespace for memory. The process of putting data is called variable assignmentName =jerry, which is used only in the current program.Path: A bunch of used: separated paths.Hash:

, ' pwd ' behaves as if '-l ' were specified.Type:display information about command type.Shell built-in command: Shell builtinExternal command: A binary executable program or script with the same name as the command in the file system Environment variables: named memory space$PATHEnv:env-run a program in a modified environmentPrintenv:printenv-print all or part of environmentHash:remember or display program locations. Search Time: O (1)-D Forget the remembered location of each NAMEDate:date-prin

Allow non-root users to use "sudo"Root login system, execute "visudo", add a new rule according to the example (remember the password entered is the current user password, not the root password)#不需要密码执行sudo命令Hadoop all= (All) Nopasswd:allDateTime Stamp to dateDate-d ' 1970-01-01 UTC 1312438633.724 seconds ' + "%y-%m-%d%T"#显示现在日期Echo ' date-d now +%y%m%d '#显示昨天日期Echo ' date-d yesterday +%y%m%d '#加减时间Date +%y%m%d–date= "-1 day"Date +%y%m%d%h–date= "-1 h

(can provide shell command execution efficiency) Hash Grammar hash [Options ...] [Arguments] Options -R clear Hash table record -P add command to hash table Date Time management Hardware clock: Clock System clock: Date Hwclock -w:--SYTOHC -s:--hctosys Get help with the use of commands Internal command: Help COMMAND External command: COMMAND--help Command manual: Manual Man [NO.] COMMAND Sub-chapters: 1: Use

2043021. View all the files in the directory to occupy memoryDu-sh"System administration Commands"Who shows online loginClear Clear ScreenHostname Display host nameTop dynamic display currently consumes the most resources process informationDF View disk size df-h with unit display disk informationIfconfig Viewing network conditionsPing Test network connectivityNetstat Displaying network status informationK

Tags: view int advanced Common STR config mpstat tor PCRView hardware information related commands (8)IfconfigFreeFdiskEthtoolMii-toolDmidecodeDmesg LspciOther (19)EchoPrintfRpmYumWatchAliasUnaliasDateClearHistoryEjectTimeNohupnc XargsExecExportunsetTypeSystem performance Monitoring advanced commands (12)Memory, CPU:TopFreeVmstatMpstatIostatSarProcess:IPCsIpcrmLsofStraceLstraceLoad:UptimeMountUmountDf

directory. The--max-depth=0 function is the same as the-s option Vmstat Reporting statistics for virtual memoryVmstat 2 5 #每二秒显示一次系统内存的统计信息, total 5 timesSAR (System activity Reporter report) is one of the most comprehensive systems performance analysis tools available on LinuxSar-u-O Test 10 3Note: Samples are sampled every 10 seconds, sampled 3 times in a row, observe CPU usage, and store the sample results in binary form into the file test in the current directorySar-q 10 3 Note: Sample ev

almost all of the operations under Linux can be implemented by the command line, familiar with the command line operation can not only bring convenience to our work, but also have a significant effect on the improvement of our working efficiency. To summarize, a few common commands and how to use Linux. User Management New user Add useradd UserName After crea

Tags: win need stat inux telnet algorithm listen upload off Ifconfig command View and configure network status commands Turn off and start the NIC Ifdown NIC Device Name Disable the NIC device Ifup NIC Device Name Enable the NIC device Querying network status Netstat options -t lists TCP protocol ports -U lists UDP p

Tags: Linux basic commandsCommon directivesls???? show files or directories???-l????? List file details L (list)???? to list all files and directories under the current directory, including Hidden A (all)Mkdir???? Create a Directory???-P????? Create directory, if no parent directory, create p (parent)Cd??????? Switch directoriesCreate an empty file with touch????echo?????? Create a file with content.Cat??????? View File Contentscp????????Mv??????? Mov

a system Architecture of LinuxEverything in Linux is a file .These files are at the top of the system directory "/" / is the root directory/ directory Below is a level two directory these directories are automatically created when the system is installedThe role of the secondary directory/bin # # binary executable file is a system command/sbin # # System Management Command storage location/Boot # # boot partition, responsible for system startup/dev #

user, then the system automatically creates a group name that is the same as the user name. (5) Userdel: Delete User(6) passwd: Set User passwordpasswd User Name(7) SU: Switch user nameThe user name that SU needs to switchSu-the user name that needs to be toggled, after switching the user, will also actively jump to the user's home directoryNote: If you have an Ubuntu platform, you need to add "sudo" before the command, and if you need an administrator to operate on some operations, Ubuntu

owned user right The 第5-7 character rw-represents the currently owned group permission 第8-10 character r--represents other user rights Then the permission for the file is 664chmod permissions to modify a file or directory. Format: chmod [parameter] permission file or directory nameThe Chown command is used to modify a file or directory to belong to the main and owning group. Format: chown [parameter] owner: owning group file or directory name The command parameters of chmo

1. The command format for HDFS operations is1.1hadoop fs-ls1.2 Hadoop fs-lsr1.3hadoop fs-mkdir1.4hadoop fs-put1.5hadoop fs-get1.6hadoop fs-text1.7hadoop fs-rm1.8hadoop fs-rmr2.hdfs when a block partition of data storage, if the file size exceeds block, then according to block size partition, rather than block sizes, divided into a block, is the actual data size.Permissiondenyexception Insufficient Permissions **********HDFs