Quick Query manual for common Linux commands (1)

Back: change the Cancel button in authconfig to the Back button.-test enables authconfig to be run only by the root user.

System settings and management

1. alias

Note: Set aliases and display aliases for commands.

Syntax: alias [alias] = [command name]: alias for [command name.

Alias [alias]: displays the command corresponding to the [alias.

Alias: displays all alias settings.

2. apmsleep

Description: the instance is suspended or waiting.

Syntax: apmsleep hh: mm

Parameter: hh: mm indicates the time when the instance is suspended or waiting.

3. authconfig

Description: provides users with a graphical interface for configuring NIS in/etc/sysconfig/network.

Syntax: authconfig-back-test-nostart

Parameter:-back: change the Cancel button in authconfig to the Back button.-test enables authconfig to be run only by root, and other users cannot save the modification; -nostart: the authconfig change settings take effect after the system is restarted.

4. aumix

Description: changes the sound effect settings.

Syntax: aumix [-] [+ |-] [<-amount>] | [[] | R | P | q] [-d] [-f] [-h] [-I] [-L] [-q] [-S]

Parameter:-channel parameter. for each channel, the +/-option is used to increase/decrease the original intensity: (^ 60090103a ^)

-D: specifies the audio device file. the default value is/dev/mixer.-f indicates the file that stores/reads the device;-h indicates the information displayed during use;-I indicates running aumix in interactive mode, use the GUI;-L from S | HOME /. aumixrc or/etc/aumixrc reads the settings;-q queries all devices and displays their locations;-S stores the settings to S | HOME /. aumixrc.

5. bg

Note: place commands in the background for running.

Syntax: bg [job]

Parameter: job command job number.

6. cardmgr

Note: The PCMCIA device management program manages the insertion and removal of PCMCIA slots.

Syntax: cardmgr [-Vqdofv] [-c configpath] [-m modpath] [-p pidfile] [-s stabfile]

Parameter:-V displays the version information.-q is set to quiet mode.-d is used to check the dependency between modules when the device driver is loaded.-o is used to configure the current PCMCIA card; -f is executed on the foreground, instead of running the program as a deamon.-v displays detailed information about Command running.-c configpath searches for the configuration database and script of the PCMCIA card in the configpath directory, the default value is/etc/pcmcia.-m modpath searches for the loadable kernel module in the modpath Directory.-p pidfile writes the PID of cardmgr to the pidfile file, the default value is/var/lib/pcmcia/stab.-s stabfile writes information about the current slot to the stabfile. the default value is/var/lib/pcmcai/stab.

7. chage

Note: Set the password validity period. This command can only be run by the root user.

Syntax: chage [-m mindays] [-M maxdays] [-d lastday] [-I inactive] [-E expiredate] [-W warndays] user name

Parameter: minimum interval between-m mindays password changes;-M maxdays password validity period, maxdays + lastday is less than the current date, you need to change the password; -d lastday: the date on which the password was last changed;-I inactive blocked the account only after the password expires inactive days;-E expiredate set the user account time period; -W warndays: the user is prompted to modify the password before the user needs to change the password.

8. chkconfig

Note: checks and sets various services of the system.

Syntax: chkconfig [-- add] [-- del] [-- list] [System Service]

Chkconfig [-- level <等级代号> ] [System service] [on/off/reset]

Parameter:-add adds the specified service so that chkconfig can manage it.-del deletes the specified service and is no longer managed by chkconfig; -list lists all system services that can be managed by chkconfig.-level <等级代号> Specifies the execution level in which the system service is enabled or disabled. the level code is 0 ~ 7. on enables the system service at the specified execution level. off disables the system service at the specified execution level. reset resets the system service at the specified execution level.

9. chroot

Note: change the root directory.

Syntax: chroot [destination directory] [execute command…]

10. depmod

Command: analyze the dependencies of the load-able module.

Syntax: depmod [-adeisvV] [-m <文件> ] [Module name]

Parameters:-a analyzes all available modules;-d executes the troubleshooting mode;-e outputs symbols that cannot be referenced;-I does not check the version of the symbol table; -s records errors in system records;-v displays detailed information during execution;-V displays version information;-m <文件> Use the specified symbol table file.

11. exec

Note: execute the Specified Command. after exec executes the command, the control will not be handed over to the original shell, so the user will log out.

Syntax: exec [-cl] [-a name] [command <指令参数> ]

Parameter:-c executes the command in an empty environment;-l adds a break number before the initial parameter, and then transmits it to the command;-a name transmits the name as the initial parameter to the command.

12. export

Description: sets or displays environment variables.

Syntax: export [-fnp] [variable name] = [variable setting value]

Parameter:-f indicates the function name in [variable name].-n indicates the deletion of the specified variable. the variable is not actually deleted, but is not output to the execution environment of subsequent commands; -p: list all environment variables that the shell assigns to the program.

13. fg

Note: switch the program or command to the foreground for execution.

Syntax: fg [job]

Parameter: job command job number.

14. free

Description: displays the memory status, including the physical memory, virtual memory, and shared memory segments.

Syntax: free [-bkmotV] [-s <间隔秒数> ]

Parameter:-B displays memory usage in Byte units;-k displays memory usage in KB units;-m displays memory usage in MB; -o: The buffer adjustment column is not displayed;-t: the total memory;-s <间隔秒数> Observe the memory usage continuously and set the check every several seconds.

15. groupadd

Creates a user group.

Syntax: groupadd [-g gid [-o] [-r] [-f] group name

Parameter:-g gid specifies the group ID-GID value;-o reuse group ID;-r is used to create system accounts;-f forces the creation of new user groups.

16. groupdel

Delete a user group.

Syntax: groupdel group name

17. groupmod

Modify user group information.

Syntax: groupmod [-g gid [-o] [-n group_name] group name

Parameter:-g gid re-specifies the group ID value;-o re-uses the group ID;-n group_name changes the user group name.

18. grub

Note: In Linux, there is another multi-operating system boot manager except LILO.

Syntax: grub [-- batch] [-- boot-device = DRIVE] [-- config-file = FILE] [-- device-map = FILE] [-- hold] [-- no-config-file] [-- no-curses] [-- no-floppy] [-- probe-second-floppy] [-- read-only]

Parameter:-batch allows batch processing.-boot-device = DRIVE sets the start partition. the default value is 0 × 0.-config-file = FILE sets the configuration file name, the default value is/boot/grub. conf;-device-map = FILE use the specified device mask file;-hold waits for the debugger to start;-no-config-FILE does not use the configuration file; -no-curses does not support the mouse;-no-floppy does not support the soft Drive;-probe-second-floppy detects the second soft Drive;-read-only is read-only.

19. halt

Note: shut down the system.

Syntax: halt [-dfinpw]

Parameter:-d should not be recorded in the wtmp (Login record file);-f, regardless of the current runlevel, does not call shut down, that is, force the system to shut down;-I before shutting down the system, disable all network interfaces.-n do not execute sync before shutting down the system (write all data in the cache to the hard disk);-p disables the system and power off; -w records only in wtmp, instead of actually ending the system.

20. kill

Note: The program (process) being executed will be terminated.

Syntax: kill [-s <消息名或编号> ] [Program]

Kill [-I <消息编号> ]

Parameter:-s <消息名或编号> Specifies the message to be sent. The process number of the [program] program can be obtained using the ps command;-I <消息编号> Lists message names. if a message number is specified, only the message name is displayed.

21. last

Lists information about users who have logged on to the system.

Syntax: last [-aRx] [-n <个数> ] [User account name…] [Terminal number…]

Parameter:-a displays the host name or IP address of the user who logs on to the system in the last row.-R does not display the host name or IP address of the user who logs on to the system; -x: displays information such as system shutdown, restart, and Operation grade change.-n <个数> Specify the number of recent logon users to view. [user account name…] Specify to view the logon records of a user account; [terminal number…] Specify to view logon records from a terminal.

22. lilo

Note: The most common multi-operating system boot manager in Linux.

Syntax: lilo [-clqtV] [-B <外围设备代号> ] [-C <配置文件> ] [-D <延迟时间][-d<识别标签][- f< 几何参数文件> ] [-I <开机扇区文件> ] [-I <识别标签> ] [-M <映射文件> ] [-P] [-r <根目录> ] [-R <执行指令> …] [-S <备份文件> ] [-S <备份文件> ] [-UU <peripheral device code>] [-v…]

Parameter:-c uses the compact mode. this parameter stores all files required for system startup in consecutive sectors;-l generates linear sector addresses;-q lists the mapped system core files; -t is only used for testing. do not modify the startup sector and ing file.-B <外围设备代号> Specifies the peripheral code for lilo installation.-C <配置文件> Specify the lilo configuration file. the default value is/etc/lilo. conf;-d. <延迟时间> Set the boot delay time. the default value is 5 seconds.-D <识别标签> Specifies the OS to be started by default after the instance is started.-f <几何参数文件> Specify the disk's geometric parameter configuration file. the default value is/etc/disktab;-I <开机扇区文件> Specifies the sector file to be used for boot. the default value is/boot. B;-I <识别标签> Display the location where the system core is stored;-m <映射文件> Specify the ing file. the default value is/boot/map.-P determines whether to fix or ignore partition table errors.-r <根目录> Set the directory to be mounted to the root directory when the system starts.-R <执行指令> Set the first command to be executed when the system is started next time;-s <备份文件> Lilo writes the old boot sector content to the specified backup file before generating a new boot sector;-S <备份文件> If the specified backup file exists, overwrite the file forcibly, and the-s parameter does not overwrite the file;-u <外围设备代号> Uninstall lilo on the specified peripheral device and check the timestamp;-U <外围设备代号> The same as-u function, but does not check the timestamp;-v shows the command execution process.

23. lsmod

Description: displays the kernel modules loaded into the system.

Syntax: lsmod

24. lspci

Description: displays the bus and device information of all system PCI devices.

Syntax: lspci [-bmMnt] [-v [v] [-x [xx] [-s] [[:] [] [. [] [-d []: [] [-I] [-p]

Parameter:-B displays IRQ and I/O addresses,-m copies PCI device data,-M searches for all PCI devices, and-n displays PCI vendor code; -t. all buses, bridges, devices, and their relationships are displayed in a tree chart.-v displays details.-vv displays more details; -x displays the first 64 bytes of the PCI configuration space in hexadecimal format;-xx displays all contents of the PCI configuration space in hexadecimal format;-s [[]:] [] [. []: displays devices that meet the specified bus, slots, and functions.-d []: [] displays devices that comply with the vendor ID and device ID.-I sets the file as the PCI ID database, the default value is/usr/share/pci. ids;-p
Set dir as the directory containing PCI Information. the default value is/proc/bus/pci.

25. mkbootdisk

Note: Create a Linux boot floppy disk of the same version as the current system.

Syntax: mkbootdisk [-- device <设备名> ] [Kernel version]

Parameter:-device <设备名> The device name of the floppy disk, usually/dev/fd0; [Kernel version] Kernel version of the current system.

26. modinfo

Description: displays kernel module information.

Syntax: modinfo [-adphV] [-f format_string] module file name

Parameter:-a indicates the author of the kernel module;-d indicates the description of the kernel module;-p indicates the parameters supported by the kernel module; and-h indicates the help information; -V indicates the version information.-f format_string indicates a string of any format, which is used to extract module information from the ELF part of module_file.

27. mouseconfig

Note: Graphical mouse configuration tool.

Syntax: mouseconfig [-- expert] [-- noprobe] [-- kickstart] [-- device] [-- emulthree] [mousetype] [-- test]

Parameters:-expert allows you to manually set relevant parameters, ignoring automatic system settings;-noprobe does not detect the mouse;-kickstart quick mode; -device specifies the hardware port used in quick mode.-emulthree uses two-key mouse to simulate a three-key mouse. mousetype specifies the mouse type used in quick mode; -test allows non-root users to use mouseconfig, but cannot be used for setting.

28. ps

Views the currently running process.

Syntax: ps [-aeHuwx] [-- group <用户组名> ] [-- Tty <终端号> ] [-- User <用户账号名> ]

Parameters:-a indicates the processes executed on all terminals;-e indicates all programs;-H indicates the tree structure, indicating the relationship between processes; -u displays the status in the user-based format;-w uses a wide display mode;-x displays all programs without distinguishing terminals;-group <用户组名> Only processes started by the specified user group are displayed.-tty <终端号> Only processes started on the specified terminal are displayed.-user <用户账号名> Only processes started by the specified user are displayed.

29. reboot

Note: Restart the Linux system.

Syntax: reboot [-dn]

Parameter:-d does not write the restart into the log/var/tmp/wtmp;-n does not check whether an uncompleted program is used before the restart, and restarts immediately.

30. shutdown

Note: shut down the Linux system and computer.

Syntax: shutdown [-fFhr] [-t <称数> ] [Time] [warning information]

Parameter:-f does not check the disk when it is restarted;-F does not check the disk when it is restarted;-h disables the Linux system and shuts down;-r disables the Linux system and restarts; -t <秒数> Run the shutdown command a few seconds later. [time] the time for executing the shutdown command is set in hh: mm or + mm mode. you can also use now to execute the command now; [warning information] it can be used to send information about shutdown to every user logged on to the system.

31. su

Note: You can use su to temporarily change a user to another user account for logon.

Syntax: su [-fl] [-c <指令> ] [User account]

Parameter:-f if you log on with another user account, you will not be able to read the user's account. profile, etc.-l the working directory is also changed after the user account is changed, just like the new login of the user account;-c <指令> After executing the specified command, return to the original user account.

32. who

Note: all user information that has been logged on to the system is displayed.

Syntax: who [-Hiq]

Parameter:-H indicates the title of each information.-I indicates the user's idle time. There is no action within one minute and it is marked as ". ", no action within one day, marked as" old ";-q only shows the total number of users currently logged on to the system