r2d2 commands

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

= 255.255.255.0GETEWAY = 192.168.1.1ONBOOT = yesTYPE = EthernetNote: BOOTPROTO can only use the configured IP address in static mode.Modify dnsVim/etc/resolv. confThe modification takes effect immediately and starts as well. FormAdd nameserver = ***.***.***.***Up to three candidates can be selected as candidates after the previous failure. Modify host nameEffective immediately:Hostname fc2Start effective:Vim/etc/sysconfig/networkThe format is as follows:NETWORKING = yesHOSTNAME = rh-linux.fc.or

functions:Specific characters used for filtering/searching. Regular expressions can be used in combination with multiple commands. 3. command parameters:-A -- text # Do not ignore binary data.- -- After-context = # In addition to displaying the column that conforms to the template style, the content after the row is displayed. -B -- byte-offset # indicates the number of the first character of the line before the line that conforms to t

position you selected, both soft links and hard links are synchronized.Ln commands are used to link files or directories. for example, if you specify more than two files or directories at the same time, and the final destination is an existing directory, all the previously specified files or directories will be copied to this directory. If multiple files or directories are specified at the same time and the destination is not an existing Directory, a

keyword], apropos [any keyword], command -- Help [Root @ localhost ~] # Apropos fstabendfsent [getfsent] (3)-handle fstab entriesfstab (5)-static information about the filesystemsfstab-Decode (8)-run a command with fstab-encoded encode (3) -Handle fstab entriesgetfsfile [getfsent] (3)-handle fstab entriesgetfsspec [getfsent] (3)-handle fstab entriesnfs (5) -fstab format and options for the NFS file systemssetfsent [getfsent] (3)-handle fstab Entries [root @ localhost ~] # Whatis lsls (1)-List

Ipcclean removes internal and isolated signal sharing signs from the stopped PostgreSQL Server Pg_ctl start, stop, and restart the postgresql service (for example, pg_ctl start starts the postgresql service, which is the same as service PostgreSQL start) Pg_controldata displays the internal control information of the postgresql service Postgres PostgreSQL single-user database service Postmaster PostgreSQL multi-user database service 4. Psql is the most important client program. To e

If you do not use the built-in command but fork to output a sub-process and execute it in the sub-process, the path of the parent environment will not be changed. After the execution is completed, it returns to the parent shell environment, and the PWD of the environment is not changed at all, so it will fail. You can write a script to test CD. Sh. #! /Bin/bashCD/home/ Run./CD. SH and you will find that the current shell path has not changed. Similarly, if you want to change many parameters

Common Linux commands and common linux commandsDirectory: relative path and absolute path. Absolute path: the path is written in the root directory, for example,/usr/share/doc. Relative Path: the path is not written by/. For example, if/usr/share/doc is to be written under/usr/share/man, you can write it as [cd .. /man: This is the relative path. Cd: Switch directory; pwd: display the current directory; mkdir: Create a new directory; rmdir: d

Common vi/vim commands and common vivim commandsWorking Mode INSERT command A attaches text behind the cursor A adds text at the end of the line I insert before the cursor I insert text at the beginning of the line O Insert a new row under the cursor O Insert a new line to the cursorLocating command H move one character to the left/the arrow to the left J. Move down one row/down arrow K move up one row/Up Arrow L move one character to the right/the

Common CentOS commands and common centos commandsSystem Command yum command Yum makecache yum generation CacheYum list installed mysql * check whether the * package has been installedRpm-qa | grep mysql * check whether the mysql * package has been installedYum list mysql * check whether there is an installation packageYum search mysql * search package Restart Reboot-h now Shutdown Shutdown-h now -H to avoid MySql corruptionView CPU More/p