Shell Note 3

1. Cal Command: Date display

2. Cat/proc/meminfo: Memory usage Query

3. Free command: Memory detail Query

4. Arch command: CPU architecture display

   Displays the architecture of the current system, for example:

   #arch

   x86_64
   

5. CAT/PROC/CPUINFO:CPU Information Display

6. Cat/proc/modules: Query The current system is loaded module

Linux system contains information: File system, kernel module, hardware information, startup parameters and so on.

2. Proc File system: Accessing system Kernel Information

   (1) proc is not a real file system, does not occupy external memory space, but simply accesses the Linux kernel data provider as a file.

   (2) In this directory, a process that runs on each system in which a digitally named directory corresponds, which is the PID number of the process.

   (3)/proc/filesystems to view the file system types supported by the current system

   (4)/proc/uptime to see when the system is running

   (5)/proc/interrupts can view the current system use of the interrupt number

3. Modinfo Command: Kernel module information

   (1) Option description for Modinfo command

   
   

   Options	Description
   -A, author	Show Module author
   -D,--description	Display Module Description information
   -l,--license	Show Module License
   -n,--filename	Show module file name
   -p,--parameters	Display the parameter information supported by the module
   -v,--version	Display version Information
   -h,--help	Display Help information

5. Cat/etc/issue Command: Current release version of the system

7. Cat/proc/version: View the current version of the system kernel

9. Cat/proc/partitions: View System Current partition

11. cat/proc/interrupts command: Display interrupt information

13. Cat/proc/filesystems command: Common file system Information

15. DMESG: Start information query

    The DMESG command, which detects and controls the cache of the kernel, is typically used to display the kernel internal cache information at the last boot of the output system.

In the daily work may encounter many need to set their own information, such as system time, hardware clock, kernel parameters, boot boot and so on.

1. Date command: System time display and settings

   Use the date--help command to see options for the date command
   

2. Hostname Command: Host name display and settings for the current system

3. Hwclock command: Hardware clock display and setup

4. Hash command: Display, add, or clear a hash table

5. Sysctl command: Setting the system core parameters

File System Information Display

1. Echo

2. Isosize

   Displays the size of the output iso9660 file system.

3. Minfo command: Display of various parameters of MS-DOS file system

4. PWD command: Displays the current working directory

5. ProcInfo command: Display of System state information

6. Stat command: Display of file/file system details

Operating System Information Query

2. uname command: Display of operating System information

4. Vmstat command: Display of statistics for virtual memory

6. Uptime command: Display of operating information of the system

8. Locale command: Language settings for the current system

10. Tload command: System load display

11. RunLevel command: System run level display

    
    

    Run level	Description
    0	Shutting down the system
    1	Single-User mode
    2	Multi-user mode, but does not support NFS
    3	Secure Multi-user mode
    4	Keep
    5	Graphical user mode
    6	Restart

    The initial operating level setting of the system is stored in the file/etc/inittab.

    The RunLevel command reads the system's/VAR/RUN/UTMP file, reads the system's RunLevel record, and then outputs the previous and current runlevel, denoted by n if the last system's RunLevel is not recorded.

13. Lsmod command: Display of all loaded modules

Process Resources

1. Top command: Process information display

   
   

   options
   b	batch processing mode
   c
   i	Ignore idle process
   s	privacy mode
   s	cumulative mode
   H	Show all threads
   q
   -p pid	monitor specified process
   -n iterations

3. IPCS command: IPC device information display

5. Time command: Show between Process execution

   CPU time, User time, System time

   [Email protected]:~# time

   
   

   Real 0m0.000s

   User 0m0.000s

   SYS 0m0.000s

7. Pstree command: Display the program in a tree view

9. PS Command: monitoring process

11. PMAP command: Displays resource usage information for a program

13. Jobs Command: Background jobs

    Show jobs that are currently executing in the background

15. MEV command: Monitor mouse condition

17. Fuser command: Using a socket or file recognition process

    #fuser-L display list of signals

    #fuser-A/root shows the processes associated with the root directory (including files being used and unused)

    #fuser-K/root kills all processes associated with the/root directory

Linux Terminal command Line operations

1. Fgconsole command: Displays the current number of virtual terminals

2. History command: Show historical instructions

3. Gdialog command: Shell Script Creation dialog box

4. Yes command: continuous output of string

System administration Commands

2. sudo command

   The sudo command, which executes the specified command as the other user of the system, can only be executed by the user allowed in the/etc/sudoers file.

   When the user executes the sudo command, they must enter the password before they can obtain the appropriate identity, which is valid for 5 minutes.

4. RSH command: Remote user settings Login Shell

6. CHSH command: Shell when switching system login

8. Clear command: Clears the terminal screen

10. Rlogin command: Intelligent remote Login

12. Kill command: End Process

14. Killall command: Kill a process with the same name

16. Nice command: Process-priority switch

18. Pgrep command: Find a process that meets the criteria

20. PIDOF command: View the process ID of the running program

22. Renice command: Set process priority

24. EXEC command: Handing over control

    The EXEC command is used to surrender control after the specified command has been executed. Because control will no longer be handed over to the original shell, you will be logged out.

26. Init command: Parent process of a process

    The init command is the parent process for all processes, and the init command reads the script from the/etc/inittab file and executes the scripts.

    For example, switch the system to run level 0, which is shutdown mode. #init 0

    For example, to restart the system, the command is shown below. #init 6

28. BG Command: Background execution program

    For example #bg 3

30. Wait command: Waits for the program to return status

    The wait command is a shell built-in command that waits for the specified process to end and returns the end status value. If you do not specify a waiting process, wait waits for all processes to end.

32. Rmmod Command: Delete module

34. Watch command: repeatedly executes commands

    Executes the specified command repeatedly in full-screen mode and outputs the output to a standard output device.

    #watch-N Ten LS

36. Sleep command: System hibernation

38. Suspend command: Suspend execution of Shell

System Maintenance Commands

1. Export command: Set environment variables

2. HostID command: Host digital ID

3. Alias Command: Set alias for command

   #alias p=pwd pwd alias P

4. Eval command: Multiple commands are executed at the same time

   #eval ls; Pwd

5. Dircolors: Configuring the LS command display color

6. Set command: Sets the shell execution mode

   The set command can set how the shell executes, and it can also display and set environment variables through command set.

7. up2date command: Upgrade red Hat Linux system

8. Unalias command: Delete the specified alias

9. unset command: Delete a variable or function

Shell Note 3