Linux System Administration Commands

Some basic commands for system administration commands

APMD Advanced Power Management (APMD command is responsible for BIOS Advanced Power Management (APM) related records, warnings, and administrative work)

APMD "Options" "percent change" "percent value"

-P "percent change" when the magnitude of the power change exceeds the set percentage change, the event is logged

-U sets the BIOS clock to UTC

-V Logs all APM events

-W percent value if the battery is not in charge, the battery store age is below the set percent value, and the warning message is logged at the alert layer of the Syslog

-W issue a warning message to everyone

Apmd-w 15-w Warning All users when the battery level is below 15%

Apmd-q the ability to emit a warning if the battery is below a certain percentage

Apmd-p 15 Event is logged when the power change amplitude of the strength is 15%

Apmsleep APM into hibernation computers, especially laptops, can set the alarm time by using RTC and go into hibernation or alternate mode

APM is actually an acronym for Advanced Power Manager, which is a management mode for controlling and managing computer hardware power through the operating system, which is actually a computer power management program (software).

Apmsleep "Options" "+" hh:mm

-S enters sleep state

-S into standby state

-W Wait Time

-P waits for a warning event to match the actual time

-N does not work with APM BIOS hibernation computer, only set alarm time and wait time

-D output Task information on the screen

HH:MM specifies an event that enters a pending or waiting state

Apmsleep +0:00 immediately sleeps

Apmsleep-s +3:00 into hibernation for 3 hours

Apmsleep-s 11:00 Enter standby time until 11:00 next day

Apropos find the name and description of the user manual (find the keyword in a specific intermittent PST database file that contains system commands, and then output the results to standard output)

Apropos keyword

-D Output Debugging information

-V Output verbose warning message

The-w keyword contains a wildcard character

-A requires all keywords to match simultaneously

-L do not truncate the output by the end width

Apropos Useradd find a manual section with Useradd in the title

Apropos Editor---------------------editor---------------

Architecture of the arch output host

Alias setting aliases (if only alias is entered, all current alias settings are listed)

Alias ls = ' ls-cf change the LS command to display information in the list and annotate the output

Alias r= "Fc-s" creates a command to repeat the previous entry in the command history file

Alias du = du \ k uses 1kb unit for du command

Alias PSC = "Ps-ef | grep Dee "creates a command for user Dee to display all active processes

CD Switch Directory

Clear clear the terminal screen ==ctrl +l

Clock system RTC time setting. RTC is the computer's built-in hardware time, which executes this command to display the current time, adjust the time of the hardware clock, and set the system time to coincide with the time of the hardware clock

Clock "features" "Options"

function: -R reads the hardware clock and prints the results

-S set system time from hardware clock

-W Sets the hardware clock from the current system time

Primary option-U hardware always remains in UTC time

-localtime hardware clock remains local time

--DATE Specifies the hardware clock time to set

Cal Display Calendar

Cal "Options" "Sun Moon Year"

-L only displays the current month "default"

-3 shows last month, month and next month

-S Sunday as the first day of the week

-M Monday as the first day of the week

-Y output year

Chroot Change the root directory (replace the root directory with the specified destination directory)　　　　　

Chroot "Options" New root "command"

--userspec= User: Group

--group = Group list, specifying a list of user groups that can provide a selection

Run the PWD command to use the/usr/bin directory as the root file system Mkdir/usr/bin/lib Cp/usr/ccs/lib/libc.a/usr/bin/lib chroot /usr/bin pwd

Run the Korn shell word Shell to have another file system as the root filesystem chroot/var/tmp/usr/bin/ksh

Date Displays or sets the system time

Date "necessary option" "Optional Option"

-D Displays the time specified by the string

-I output time according to iso-8601 datetime format

-S set time according to STRNG

Format percent

%a Day of the week

%b Month

%c Date and time

%h=%d

%H hours

%m Month

Date Displays dates

Date + "%r%a%d

Date 0217145290 set February 17, 1990 14:25:00

DMESG Display boot information (boot information is stored in the/var/log directory named DMESG file)

Dircolors sets the color used by the LS command when displaying a directory or file

Dircolor "color profile" Dircolor "-bcp" "--heip" "-version"

-B

-p display Pre-set

Depmod Analysis Module (analysis of the dependencies of the loaded modules for Modprode to be used when installing the module)

Depmod "option" "Module name"

-A analysis of all available modules

-D performing an error-Troubleshooting mode

-E output symbols not referenced

-M "file" using the specified symbol table file

-S logs an error in the system record

echo Display text line

echo "Options" ... "STRING"

-N does not output newline characters at the end of a line

-E allows interpretation of translatable characters

echo Please insert diskette to output a message to standard output

Write the message to the standard error output echo Error:file already exists. >&2 If the &2 is not written, the message will be written to the standard output.

EXEC finishes command and surrenders control.

-C Execute specific commands in an empty environment

EXEC ls exits after the LS command finishes executing

Exit shell

Eject Eject media (exit the pull-out device.) If the device is already attached, eject will now write the device out at exit)

Eject "Options" "Devices"

-A open hanging wall auto eject function

-D Show Default device

-F Eject Floppy

-T Close Tray

Eject/dev/cdrom Eject Optical Drive

Eject-r/dev/sda4 eject the specified device

Enable or disable shell commands (start or close shell built-in commands)

Enable "Options" "Built-in Commands"

-N Closes the specified shell built-in command

-a displays all commands related to Shel shutdown and startup

-F read commands from the specified file

Enable FG Close FG Command

FC Modify or Execute commands

FC "Options"

-E Text Editing program specifies the text editing program used by default is Fcedit editor VI

-l Lists all commands in the first and end ranges only

-N Show command list is not display number

-R Displays the list of commands in reverse order

Fc-l-5 Lists the 5 commands that were previously run

Fgconsole shows the number of virtual terminals

Free displays memory information (including ...). such as

Free "Options"

-B Displays Memory usage status in bytes

-K displays memory usage in kilobytes

-M-----MB------------------------------

-t display memory sum column

-S "set number of seconds" continuously observe memory usage

Free-t displaying memory usage as a sum

Fwhois displaying user information

Getty setting Up Terminal mode

Linux System Administration Commands