Summary: Man, info, Hwclock, Cal, type, which, DirName, BaseName, who, which, Whatis, Makewhatis, hash, TTY

Man , info, help, date, Hwclock, Cal, shutdown, reboot, Halt, Poweroff, type, CD, which, DirName, BaseName, who, which, Whatis, Makewhatis, Echo, hash, TTY tac:cat display the file file in reverse order ...: View the format of the contents of the Files # mkdir ' Date+%f-%h-%m-%s ' Creates a directory with the current time command, for example 2014- Geneva- One- -- -- -;
Rmdirwho: View all users logged on on the current system and their information
TTY view displays the current terminal end device file serial terminal/dev/ttys# Physical Terminal/dev/Console Virtual Terminal/dev/tty# graphic Terminal pseudo terminal (analog terminal)/dev/ttys#Ctrl+C: Cancel the current program
Shift+pageup/Pagedownfeatures of the Linux file system:1, the file name can be used except/any character other than the total length of 255;2, strictly case-sensitive, ABC, Abchash: View the directory path where the executed file of the used command or program is located the shell has set up multiple paths in advance with a variable (path), and when the user enters the command, The shell automatically looks under the path (left-to-right) to see the executable file with the same name as the command is found and executed commands are saved to a hash lookup table; You can use the hash command to view this table which: view a specific path to an executable program: using the which command Format of the commands: command options arguments[]: Represents the optional content in parentheses. {,}: the content inside the parentheses is used as a unit of use, respectively. For example X{a,b} is equivalent to XA,XB|: Alternatively, you can select only one<>: You must specify the contents in parentheses ... : Multiple built-in commands can appear for similar content: Help command name built-in command helper information, using format # Assist CD
External command: # command--Help information for external commands, using format # dirname--Help 
User manual: manualman:# man commands common content to be concerned with in the Help file: Name: Interpretation; Synopsis: Use format; options: option; EXAMPLES: use example; DESCRIPTION: detailed Function description options:-A shows all occurrences-D Show man speeding manual file, search path information, do not show manual page content-F with Command Whatis, you will find Help index information in the Whatis database with the keyword open-h Display man help information-k with command apropos will search the Whatis database, fuzzy find keyword-S list specifies the field and order of search such as:-S1: 1p httpd will search for man1 and then man1p directory-C Specifies that the man command search configuration file is man.config by default-K Search for a string in all manual pages, very slow-M Specifies the path of the search manual man's brief use mechanism: Turn screen: space bar: To the end of the file to flip a screen; b: Flip a screen to the file header; Enter: Flip a line to the file header;+D: Turn half screen at the end of the file; Ctrl+u: Turn half screen to file header; Text Search:/keyword: Search the tail of the file;?Keyword: Search the file header, N: the same direction as the Search command (next); N: Path Search command opposite direction (previous); add: Man can actually be a command (Common command, Administrative command), program configuration file format, system call, library call, game and other inconvenience The documentation for the collation provides a help manual; the segmentation mechanism of the man command:1-8:1: User command: User Commands instruction: a document where the consumer can manipulate instructions or executable programs in the shell2: System Call: System Calls system call: Systems-provided system call documentation3: library Call: C Library Functions Library Call: Common functions and library documents4: Device Files: Devices and special Files device: device documentation, usually in/files under Dev5: File format: Files Formats and Conventions file format: Configuration file6: Game: Games et. Al. Games7: Miscellaneous: Miscellanea Miscellaneous standards and protocols such as network protocols, ASCII code, etc., which are inconvenient to classify. 8: Administrative commands: System Administration tools and deamons Systems Directive: Administrator account available management instructions. The man is searched in the order of the chapter number of the manual, for example: #man sleep only shows the manual of the Sleep command, if you want to see the library function sleep, enter: # man3Sleepwhatis: To see which paragraphs in which a keyword is used help, you can use the # Whatis Keyword to find Makewhatis precisely: Tip: If the Whatis data has not yet been generated, you can use Makewhatis to do it manually; # Mans-k Keyword Fuzzy Find info info command: Get online documentation; Many applications bring their own documentation:/usr/share/doc/ChangeLog, INSTALL, README google:linux filetype:ppt keyword site:magedu.com redhat official document: www.redhat.com/docs/commands for the System Management class: Shutdown:shutdown [option] ... time-r: restart-h: Shut down the machine-C: Cancel the restart or shutdown command time format: now+#: #分钟以后 hh:mmreboot: Reboot system, call shutdown-Rhalt: Shut down the machine-Ppoweroff: Power off-F option Dangerous, do not call shutdown Date Time management class command: Date, hwclockdate: Show current time or modified time date [OPTION] ... [+Format]date [-u|--utc|--Universal] [MMDDHHMM[[CC]YY][.SS]] # date #修改系统时间 Date MMDDHHMM[CC]YY.SS the day of the month is divided annually (two-bit or four-digit years). Seconds seconds Display time element # date [+FORMAT]%Y: Four-bit year%y:2 bit year%m: Month%M: Minutes%D: Day%H: Month%H: When%S: Sec%D: Date MonthDayyears%F: Date used: # Date +%f-%h-%m-%s Example: Touch file-' Date +%f-%h-%m-%S ' yearMonthsDay Unix:1970- on- on xx:xx:xx%s:timestamp Common: # date +%s The number of seconds elapsed from the first years to the current time Cal Calendar Cal 2014 Calendar Linux has two clocks: hardware clock: Software clock: Read hardware clock on startup HC: Hardware physical clock SYS: system software clock Hwclock-S: Based on hardware clock,--Hctosys-W: Based on the system clock,--SYSTOHC Summary: Man, info, help, date, Hwclock, Cal, shutdown, reboot, Halt, Poweroff, type, CD, which, DirName, basename, Who, which, Whatis, Makewhatis, Echo, hash, TTY

Summary: Man, info, Hwclock, Cal, type, which, DirName, BaseName, who, which, Whatis, Makewhatis, hash, TTY