Shell programming-Day 1

Is there the same command as NBTSTAT in Linux! View other information through IP: Host Name, Mac, etc.

You can use nmblookup-a ip address.

You can also use nbtscan.

ARP command: ARP iPad. Local or ARP 192.168.1.108 or ARP-A or ARP

VI search string: switch to the command mode, and then type/youstring

#! /Bin/bash-E: Stop the script when the first error occurs.-E.

Cat pai_cache.conf | cut-F 3-D, takes three drops as the separator.

Ls-r DOC/| WC-l

Sudo Mount-T smbfs-O codePage = cp936, username = Tom, password = 123456,-l // 192.168.1.118/bu bu_mnt/

Torn

Recursively count the number of folder files.

Linux common sense:
1. Complies with POSIX development standard specifications, and Unix also partially complies with this standard.
2. Version A. B .C. A indicates that the kernel is greatly upgraded. B indicates that the kernel is greatly modified. C indicates that the kernel is greatly modified. c slightly modifies kernel 2.2.2 2.2.4 2.2.6,
The odd version is the test version, and the even version is the stable version. Therefore, we can see the even version. Currently: version 2.6.

Shell introduction:
1. A program that can drive disk rotation is called a driver or a kernel. The called interface exposed to the kernel is called a system call. API is a function.
2. Footsteps: You can directly run it without compilation.
3. CSH: System:/etc/. Login User :~ /. Login ~ /. Cshrc
Bash: System:/etc/profile User :~ /. Bash_profile. bashrc. bash_login. Profile
Vi vim:. exrc. vimrc
4. Shell programming is only applicable to small tools and is not suitable for large programs. Because every command he runs is a new process. Unlike the C language, it runs in a process.

Shell programming:
1. Step 1 :#! /Bin/bash #! The shell script is interpreted and executed using bash.
2. # Comment out exit 0 exit script $ get the variable name & run shleep 3 History in the background to view your operations
3. Run the Script: 1. chomd + x XX. Sh 2. Bash XX. Sh 3.exe c xx. Sh (the current shell will be exited) 4. Source XX. Sh

4. Miscellaneous commands:
1. Cat <End... end specifies the end character as end for output.
2. Command 2> file: Error redirection. ---- A. Out> a.txt 2> & 1 A. Out> & a.txt A. Out &> A. T
3. C language: Use spfintf () to convert a string to a value, and use atoi () atof () to convert a value to a string ()
4. (): Start a sub-Shell under the current shell to execute the command. (PWD) \ escape to continue [] ls [A-F]. *
Ls a. {txt, out}
5. Variable definition: 1. x = x 2. Declare-r a = 100-I-X... $ {var1} avoid ambiguity
6. Read var1 reads a piece of data from the keyboard man bash
7. Environment variable (uppercase): ostype PWD Lang path home seconds shlvl lineno machtype ps1ps2

Special variable: export a = 123; B = 133 Export B; set as system variable
$ @, $ * Display parameters of all locations $ # number of parameters (except the file name) $ display the PID Number of the current process $? Failed to get the status 0 of the previous command.

8. Reference: single quotes can be used to identify variables. Double quotation marks cannot be used to identify floating signs. Use a character as a command to === var =$ (PWD)
*********
= No space left or right: value = space left or right: Comparison
*******
9. Array definition: ABC [1] = 1 ABC [100] = 099 ...... B = (1 2 3 4 5)
10. Operator number:
$ {# Variable name}: length of the variable value to be tested.
Replacement OPERATOR: $ {variable name:-value} + =?
11. String processing:
Substring: $ {STR: 3: 5}
Delete a string (without deleting the body): $ {STR # matching mode }$ {STR # * cwj }## all % forward from the back.
Replace: $ {str/ABC} All $ {STR // ABC/ABC}
Comparison: Str = str-n "$ Str"-z "$ Str" is not empty.
12. Other operators: these operators are the same as those of C ++. Multiple ** operators are used to evaluate the power. Let declare-I (())
13. BC ==> 1000000*1000000 DC is used to calculate big data.
14. Program Control: Test [] and if must be used together with = left and right spaces (comparison)
* ****************: Note: When you remember to use a string, be sure to use, this avoids many problems.

Comparison expression: expression 1-xx expression 2
-Eq-ne-GT-ge-lt-Le if test "$ X"-EQ "$ Y"; then; echo "XX"; FI

15. File test:-F file existence-r user has read permission-s file size is 0! The logic is not [], and both sides must have spaces, the same as test.
16. Test the set-O environment and some configurations in the system. For example, whether to overwrite a file with the same name. Set-O colobber no/off to enable or disable this option.

Case statement: Double semicolons are used in case statements. ---- QU! I always forget to write esac as the end
Case VaR in; yes | yes) ......; [NN] O) ......; *) ......; esac

17. * Indicates all files in the current directory.
Cwj: "wildcard usage" is everywhere in shell scripts ". Good. Haha
In Shell, if case has an ending symbol. Haha
18. For statement: for VAR in *; do xxxx; done xxxx;
For (I = 0; I <10; I ++); Do xxxx; done xxxx; // echo return echo-N without carriage return, the same line is displayed.

1. If []/test then Elif else Fi // If statement
2. #### % deleted. : 3: 4: truncates 4 numbers starting from 3 subscripts. /ABC // A/A :$ {STR # * Lala} $ {str/a/A }$ {STR: 3: 5}
3. For (I = 0; I <10; I ++) do done for VAR in * do done
4. Case VaR in X) echo; y); c );;*)
Echo "plese inter A Var! "
Read inputvar
Case "$ inputvar" in
"A" | "A") echo "case ";;
"B" *) echo "case B ";;
"C") echo "Case C ";;
*) Echo "other"; // The Last One; can be added
Esac
Found during exercises:

1. When the # sign is used, our wildcard should be prefixed, and when the % sign is used, our wildcard should be back. # * 4 Ky! #4 * Bu Ky! % 4 * Ky! % * 4 Bu Ky!
Str= 01234567
Echo $ {STR: 2: 4}
Echo $ {STR #4 *}
Echo $ {STR % 4 *}

2. A = 100 B = 200 C = (A + B): This is an error. It should be like this: (C = a + B )) or C = $ (a + B ))

3 *********************** we often do this: $ (Year % 4 = 0 & year % 100! = 0 | year % 400 = 0): $ (XXX ))

------------- My examples are available in my resources. Haha