linux foundation certs

One:1.linux Common Package typesDirect-Executable RPM DEBSource code mode of gzip bzip22.RPM Package ManagementInstallation and removalRPM-IVH *.rpm Installing the RPM packageRPM-E uninstall software, the specific version number can not writeRmp-u remove the old version and install the new versionPackage information QueryRpm-q query whether to installRpm-qa all software in the query systemRpm-qi query to develop installation package detailsRPM-QL Disp

, view/etc/sudoers file permissions, if read-only permission, modify as writable permission[Email protected] user]# ls-l/etc/sudoers-r--r-----. 1 root root 4030 September 00:57/etc/sudoers[Email protected] user]# chmod 777/etc/sudoers[Email protected] user]# ls-l/etc/sudoers-rwxrwxrwx. 1 root root 4030 September 00:57/etc/sudoers[Email protected] user]#3, execute the VI command, edit the/etc/sudoers file, add the user to elevate the privileges; locate root all= (all) in the file, and add user in

VARCHAR), * * * CHAR (1)); 6: Show the structure of the table: Mysql> DESCRIBE MYTABLE; 7: Add a record to the table mysql> INSERT into MYTABLE values ("hyq","M"); 8: Loading data into a database table in text mode (for example, D:/mysql.txt) " D:/mysql.txt " into TABLE MYTABLE; 9: Import. sql File command (for example, D:/mysql.sql) mysql> usedatabase; MySQL>source d:/mysql.sql; 10: Delete Table Mysql>drop TABLE MYTABLE; 11: Clear the table from MYTABLE; 12: Update data

"We think open source components are an important part of our products and actively participate in many projects, and we continue to create new and interesting open source projects in the future," said Dirk Hohndel, chief open source officer at VMware.Hohndel leads VMware's Open source project Office to guide efforts and strategies around the use and contribution of open source projects, as well as the shared values and processes that drive VMware's engagement with the open source community thro

not wait for the thread to terminate, it is simply a request;5. Thread Cleanup handler function:#include void pthread_cleanup_push (Void (*RTN) (voidvoid * ARG); void pthread_cleanup_pop (int execute); Call to delete the cleanup program for the last pushWhen the thread executes the following action, the cleanup function is called, and the caller parameter is ARG, and the order of the cleanup function Rtn is scheduled by Pthread_cleanup_pus.A. Call pthread_exit;B. Want to use the cancellation r

than 20;awk-f ': ' nr>20 ' Test.txt7. Use ': ' As a delimiter to print all third paragraphs less than the fourth paragraph;awk-f ': ' $38. Use ': ' As a separator, print the first paragraph and the last paragraph, and the middle with ' @ ' connection (for example, the first line should be the form of "[Email Protected]/bin/bash";awk-f ': ' {print $ ' @ ' $NF} ' test.txt9. Use ': ' As a delimiter to add and sum the fourth paragraph of the entire document;awk-f ': ' {(sum+=$4)}; END {print sum} '

Iso/osi modelThe OSI seven-layer framework acts on the application layer: the layer presentation layer of the user operation: the conversion between the binary data and the display data, and also the encrypted local session layer: determining whether the network is transmitted or stored locally, whether it is a transport layer such as mail or PPT: Determine TCP or UDP protocols, and outgoing and incoming ports; FTP has different ports; TCP protocol is more stable, UDP is faster, but not reliable

Apache Web services running over port 80 on the local server, you can do this:[[emailprotected]~]#telnet192.168.10.322 #此时不需要远程主机开启了telnet服务Trying 192.168.10.3...Connectedto192.168.10.3. #已连接Escape characteris ' ^] '. ssh-2.0-openssh_5.3 #此时阻塞在这里, is waiting for us to enter the command, That means Port 22nd is on, the remote host has a service listening on this port, and if the input command does not conform to the other service's protocol, it will be forced to exit Protocolmismatch. Connec

represented by T in the pattern represented by R and replaces it with the content represented by S for the first time;Gsub (R,s,[t]): Finds the matched content in the character represented by T in the pattern represented by R and replaces all occurrences with the content represented by S;Split (S,a[,r]): Cuts the character s with the R delimiter and saves the resulting cut to the array represented by A;~]# Netstat-tan | awk '/^tcp\>/{split ($5,ip, ":"); Count[ip[1]]++}end{for (i in count) {prin

/nologin; try root to switch to the user and view its command prompt;2, the new GID for 5000 group mageedu, new user Gentoo, request their home directory for/users/gentoo, password with the user name;3, new user fedora, whose home directory is/users/fedora, password with the user name;4, the new user www, its home directory for/users/www; Delete www users, but keep their home directory;5 added additional group mageedu for user Gentoo and fedora;6, copy the directory/var/log to/tmp/directory, mod

using []2. File test-e file: Test files exist-F File: Test files are normal files-D File: Test whether the files are directories-R File: Tests whether the current user has read access to the specified file-W File: Tests whether the current user has write access to the specified file-X file: Tests whether the current user has execute permissions on the specified filesuch as: if [-f/etc/inittab] (note space)Exit # define Exit status codeBash Variable typeLocal variable (local variable) "Scope is

X. This is equivalent to "X", which is also equivalent to ' X '. \ is usually used to escape double quotation marks (") and single quotation marks (') so that double and single quotes are not interpreted as special meanings.　　2.7 Anti-quote (')　　cp 'mkdir back ' test. SH ls　　2.8 Colon (:)2.8.1 An empty colon is equivalent to "NOP" (no op, a command with nothing to do). Can also be thought of as true of the shell's built-in command. #!/bin/bash while :do echo"endless Loop " DoneEquivalent t

different, the block value is the same, B modification does not affect a, it can be understood that B is a shortcut.Six, sudo securitysudo modify config file Visudo find root all-(all) and all Plus Liang all-(root) All means linag This user can temporarily have root privileges on all IP addresses, The all of the third column means that you can use all command operations to change to Nopasswd:all so you don't need to enter a password every time you use a command.650) this.width=650; "Width=" 463

203.81.19.1Host/dig/nslookup checking Domain name resolutiond Internet Router (configuration and hardware) and ISP line issuesLog in to the router, check the superior line, call the ISP technology.e-Troubleshooting: IP address Conflicts, other people can surf the Internet, IP address conflict, ARP virus, core switch is broken,Switch loops (see logs)(b) Large area on the net:Router, ISP, core switch, ARP virus, core switch broken, gateway address occupied, switch loop2. How do I troubleshoot a s

1. Where are these useful documents?/usr/share/docExample:GRUB2 (New start-up management software)/usr/share/doc/grub2-tools-2.02 2.02 indicates version2. Ultra-Simple editor: NanoUsage: Nano test.txt//If there is no test.txt under the current directory, create a new one, if any, open the oldThe following ^ represents Ctrl^+g----> Get online Help^+x----> Leave nano, if any changes will prompt to save^+o----> Store files (under privileged conditions)^+r----> read data from other files, you can co

Without root, add regular users and manage with sudo authorization Change the default remote connection SSH service port and disable root user remote connection Scheduled Automatic server time update Configure the Yum update source to download and install the RPM package from the domestic update Turn off SELinux and iptables (iptables work scenario if a WAN IP is typically turned on, except for high concurrency) Adjust the number of file descriptors, and the process and file

]~]#getenforcepermissive1.4 Restore SELinux Method method One: Command line restore setenforce1; Method II: File reply 1, through VI, SED directly modify the configuration file 2, mv/etc/selinux/config.bak/etc/ selinux/config== Direct Overwrite profile 2nd Close firewall iptables2.1 temporarily shut down iptables View Firewall state law one:/etc/init.d/iptables Status Law II: Serviceiptablesstatus Temporary shutdown firewall law one:/etc/init.d/iptablesstop/etc/init.d/iptables stop=== executio

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/54/7F/wKioL1SFFpmhCCIvAAKeEIRn-f0877.jpg "style=" float: none; "title=" Common Devices List "alt=" Wkiol1sffpmhccivaakeeirn-f0877.jpg "/>650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M02/54/81/wKiom1SFFgaiNT6XAAJzGjtPYP8239.jpg "style=" float: none; "title=" system Run Level "alt=" Wkiom1sffgaint6xaajzgjtpyp8239.jpg "/>650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M00/54/7F/wKioL1SFFpmwmYDZAAETlrTellg871.jpg "style=" fl

is required to deleteC for need to modify[Email protected] ~]# diff a.txt B.txt4d37c6---> know that ' s tough[email protected] ~]# cat A.txtABCD12This is the what we want[email protected] ~]# cat B.txtABC12You know that ' s tough[Email protected] ~]#MV [Options] source file destination Path-I prompt if the destination has the same file name-V Show Progress when moving files, move multiple filesVery useful when-U when moving only when the source file is newer than the destination fileBefore it m

Tags: white images ctrl+h height ffffff ace command line image terminalFirst, common shortcut keysctrl+l clear screen, equivalent to clear commandCtrl+o executes the current command and displays this command again at the terminalCtrl+s block screen output, lock. (but the input command works, just can't see it)Ctrl+q Allow screen output ( often used in conjunction with Ctrl+s)Ctrl + C Terminate Command (Note the difference from CTRL + Z)For example, enter the command PING+IP address,