rs232 commands

chmodSyntax: chmod [{ugoa}{+-=}{rwx}] [file or directory] For example chmod g+w testfile[mode=421] [File or directory]-R recursive modifications such as Chmod-r 777 TestDirModify directory testfile directory files for all users with full permissionsSummary of File directory permissionsRepresents the meaning of the character permission on the file to the directoryR Read permission to view the contents of a file to list content in a directoryW Write permission can modify the contents of the file c

shut down the system.Parameters-D do not record in the wtmp.-F Regardless of the current runlevel, the system is forced to shut down without calling shutdown.-I close the entire network interface before halt.-N Halt, do not perform sync first.After-P halt, execute poweroff.-W is only recorded in the wtmp and does not actually end the system.SyncFunction Description: Writes the data in the memory buffer to disk.Syntax: Sync [--help][--version]Note: In a Linux system, when the data needs to be st

Recommend a Windows software: Everything, can quickly search to file1. File Search command: FindDo not use the Find,find range as small as possible during peak server usagefind [Range] [match condition]Example:Find/etc-name init: Find file init in directory/etc, precision search, to blur search with * matchFind/-size +204800: Look for files larger than 100M in the root directoryFind/home-user Shenchao: Find files with owner Shenchao under the root directoryFind/etc-cmin-5: Find files and directo

, for renaming8. Delete Files: RMRM-RF [File or directory]:-R Remove Directory-F EnforcementDelete the directory with-RF, or you will be constantly prompted to delete every file in the directory9. Create an empty file: TouchTouch japanlove.list10. Display file contents: Cat [FileName]-N: Show line numbers11. Display file contents: TAC [FileName]12. Paging Displays the contents of the file: more [filename](space) or F: Page turn(Enter): line breakQ or Q: Exit13. Paging Displays the contents of th

, RM; Execute permissions x: CD2. Change the file owner: ChownCommand name: Chown Command English Original: Change file ownership command path:/bin/chown Execute permissions: All user syntax: chown [user] [file or directory] function description: Changes the owner of the files or directories3. Change the owning group of the file or directory: ChgrpCommand name: CHGRP Command English Original: Change file group Ownership command path:/BIN/CHGRP Execute permissions: All user syntax: chgrp [user] [

created mkdir-p shandong/heze/danxian/yanglouzhen/liuzhaicun/t/t for recursion13. Tree Shandong View trees structure, directory organization14, man view the command's document command--help simple view Help15. Help command to view Linux built-in commands16. grep Find Code17, Tar zcvf demo.tar.gz Linux.log demo own definition name, tar.gz usual habit Linux.log will pack into demo.tar.gz18, sz demo.tar.gz download package19. Df-h Disk Utilization20, Du-sh the current directory size21, Free-m serv

testfile[[email protected] tmp]# lltotal 4-rw-r--R--.1 root root 0 Apr 08:47 filenamelogdrwxr-xr-x.2 root root 4096 Apr 08:48 testfile-rw-------. 1 root root 0 Apr 00:13 yum.log"Instance 2" Normal user create file and directory default permissions[email protected] ~]$ Touch Filename[[email protected] ~]$ mkdir directory[[email protected] ~]$ lltotal 4drwxrwxr-x.2 Zhangsan zhangsan 4096 Apr 08:48 directory-rw-rw-r--. 1 Zhangsan zhangsan 0 Apr 08:46 filenameThis article is from the "Perthon" blog

want to transfer the local 1.bmp to the remote host E:\rose, and renamed to 333.bmpFtp> put 1.bmp/rose/333.bmp (carriage return)b) mputFormat: Mput local-filesTransfers a batch of files from the local host to the remote host.If you want to upload all BMP files in the local current directory to the server E:\roseFtp> cd/rose (carriage return)Ftp> mput *.bmp (return)Note: The upload file is from the current directory of the host. For example, the FTP command running under/root/test will only be u

: LastFunction Description: Lists the current and past logged in system User Information example: lastCommand name: LastlogCommand path:/usr/bin/lastlogExecute Permissions: All UsersSyntax: LastlogFunction Description: Check the last login time for a specific user example: Lastlog lastlog-u 502 (502 for user ID)Command name: tracerouteCommand path:/bin/tracerouteExecute Permissions: All UsersSyntax: tracerouteFunction Description: Displays the path between the packets to the host traceroute www.

[user] [file or directory]Function Description: Change the owner of the file or directory (only root has this permission)Command name: CHGRPCommand English Original: Change file group ownershipCommand path:/BIN/CHGRPExecute Permissions: All UsersSyntax: chgrp [user Group] [file or directory]Function Description: Change the file or directory belongs to group example: Chgrp liming FengjieCommand name: umaskCommand English original: the User file-creation maskCommand path: Shell built-in commandEx

　　Linux Common Command Encyclopedia 100: 1, echo "AA" "Test.txt and Echo" BB "" test.txt//"empty the original file, and the content written to the file," "Put the content to the end of the file 2. chmod go+w-r/home/zhangy//To add Write permissions to group users and other users 3, TAR-TZVF test.tar.gz//List of archived content 4, Du-ah//view file list size 5, Du-sh//View the total size of all files 6, Echo ' 1+2 ' |bc-l//mathematical operation 7, uname-a//View some information of Linux ke

Netstat same usageNetstat-an |awk '/^tcp/{++sta[$NF]} END {for (key in STA) print key, "\ T", Sta[key]} ' can view all states(if the established is large, the system is busy, usually within 1000)Five, Linux under Grab Bag (tcpdump)Tcpdump-nn the first n means that the IP is displayed in digital form, if the hostname is not displayed,Look at the flow of data.Usually TCP, if you see a packet of UDP can be attacked. (DDOS UDP flood flood attack, if you encounter this can only access professional a

the default permissions that correspond to the defaults.[[email protected] ~]# umask-su=rwx,g=rx,o=rx[[email protected] ~]# mkdir/tmp/test[[email protected] ~]# ls-ld/tmp/tes Tdrwxr-xr-x. 2 root root 4096 January 8 00:32/tmp/test[[email protected] ~]#When creating a new file, the default is no execute permission for security purposes. For example, create a new Test1.txt file under the TMP directory with the following default permissions:[Email protected] ~]# touch/tmp/test1.txt[[email protect

的密码是否被锁定，以及密码所使用的加密算法名称passwd Use Example:# 修改用户 user2 的密码[[emailprotected] disk2]# passwd Five, switch user suThe SU command is used to switch between different users. Super User root switch to other users do not need to enter a password, while switching between ordinary users or switch to the superuser is required to verify the password. The SU command switches to the root user by default when no parameters are added.Common parameters of the SU command:-l 登录并改变到所切换的用户环境-c 执行一个命令，然后退出所切换到的用户环境

46.1 Mkfontdir: Creating an index of X font files 46.2 Dumpiso: Dumps the IEEE 1394 synchronous channel packets 46.3 iconv: Convert file Encoding 46.4 Hash: Display and delete hash tables 46.5 Isb_release: Displays information about LSB and specific versions 46.6 locale: Get a specific language environment 46.7 nm: List Symbols from objects 46.8 RMT: Remote disk Creation Protocol module 46.9 Lscgroup: List all the cgroups 46.10 cgclear: Uninstalling the Cgroup file sys

Tags: dir directory esc body ACK BSP Primary directory page common commandsBecause very little command line, old despised, so today record a common command line:CD Switch working directory. Represents the current directory.. Represents the top-level directory of the current directory/root directory/directory separator./Current Directory.. /go to the top level directoryLS Displays the current directory so the filemkdir Creating a new directoryRmDir Delete Empty directory, note is empty directoryV

. After reading all the content, you will exit. If you want to quit early, just press the Q key. Less is the same as more, but better than the more good can be turned upside down. The SPACEBAR can also be paged, while pressing the "J" key can be moved downward (click to move down one line) and press "K" key to move up. When you use more and less to view a file, you can click the "/" key and then enter a word carriage return so that you can find the word. If you have more than one word, you can p

Linux commands-system management commands I. Installation and logon commands Login1. RoleLogin is used to log on to the system and has the permission to all users.2. Format Login [name] [-p] [-h host name]3. Main Parameters -P: notifies login to retain the current environment parameters. -H: used to transmit user names between remote logins.If you choose to log

Yesterday, a person on the Bug-bash asked: why [--help did not output help information. Someone answered him because coreutils provided the [command to accept the--HELP option, and Bash's own [command does not accept any options.] When you execute [--help ] in Bash, of course the first priority is the internal command [, not the external command [, the execution of /usr/bin/[--help(on my Mac is/bin/[) to get the help information he wants.In fact, there are other external

Linux yum commands and yum commands Yum (all called Yellow dog Updater, Modified) is a Shell front-end Package Manager in Fedora, RedHat, and SUSE. Based on RPM package management, You can automatically download and install the RPM package from the specified server, automatically handle dependencies, and install all dependent software packages at a time, you do not need to download and install it repeatedly