bash amplifier

Linux basics-Bash command priority, linux-bash priority 1. Bash Introduction The command interpreter, also known as the Bourne Again Shell, originated from the shell. Shell, commonly known as shell, refers to a command parser in a UNIX system. It is mainly used for user-system interaction. There are many types of shells on UNIX systems. The first shell, namely, t

Job Management in Bash and bash job Management I was not prepared to write this blog, because Task Management (job Management) is very common, so I feel that there is no need to write such a thing. But if you think about it, record it. Maybe someone will use it. I wonder if you have ever encountered such a situation. When you are eager to open VIM and write code to the right corner, the operating MM or prod

Linux Command: bash language details, linux Command bash details Bash is a command interpretation language. It can execute commands that read standard input or files, execute commands, and rebound shell with nc! Basic syntax Bash-c command Root @ kali :~ # Bash-c whoami

Bash Variable type:Environment variablesLocal variables (local variables)Positional variablesSpecial variablesLocal variables:Set Varname=value: scope for the entire bash process;Local variables:Local Varname=value: Scope is the current code snippet;Environment variable: The scope is the current shell process and its child processes, (the action variable itself uses VARNAME, the value of the action variable

Bash condition test-empty string confusions: bash condition string You can use-n or-z to check whether a string is null. According to the meaning of the operator, if VAR is null or undefined, the-n test result should be false, and-z should be true. Otherwise,-n is true and-z is false. The conditional test list is used, that is, "[-n $ VAR] echo TRUE". If TRUE is output, the conditional test result is TRUE.

In our work, we often need to replace and add URLs from the text using SED. However, we often encounter the ambiguity in the SED of special characters in the URL so that it takes a lot of time to test when writing a bash script. So what are the special characters that create ambiguity? #这些都需要转义, |, \,/, ^, *, (,), [,], {,}, ',? Which, to ",/,?" " for the most important needs to transfer. For example:[Email protected] test]$ url="HTTP://

One:The shell is the shell of the Linux/unix system, and it can be understood as the command line interface, where you enter and execute the command line.Bash (born again shell) is one of the shell's most commonly used shells. you run on your Linux: PS | grep $$; If you run the result as bash, it means that the current default shell is bash.The shell is basically a command interpreter, similar to the commands under DOS. It receives user commands (such

SHELL script strategy (learning notes) -- 1.5 bash environment configuration process, -- 1.5 bash From the perspective of user login, shell is divided into two types: Logon shell: If you log on through a terminal, use the su-username command to switch users. Non-interactive shell: for example, you can use the su username command to switch between users. Open the command terminal and shell script in the grap

Bash variable types and bash Variables Local variable: it acts on the Current shell and is invalid for other shell processes other than the current shell and the Current shell Sub-processes. Assign a value to a local variable name='value' Value can be a string or a variable. The referenced variable uses $ {name}, $ name, or ''. Note: single quotes are strongly referenced, while double quotes are weak refere

In the process of reading any questions, welcome to communicate togetherEmail:[email protected]qq:1494713801when executing a script full_build.sh, I was always prompted :-bash:./full_build.sh:/bin/bash^m:bad interpreter:no such file or directoryOr remind syntax error:unexpected end of FileOne of the reasons for the above error is that the script file is in DOS format, that is, the line end of each line is i

Advanced Bash script, classic usage and cases, advanced bashIn linux, Bash scripts are very basic knowledge. You may feel very high when you listen to the scripts. Just like starting from the beginning, you may feel that script writing is a great tool. Although complicated scripts are very easy to understand, when we master the usage and skills of these scripts and practice more, we will always become a han

Description : This is a relatively simple bash script editor, but has been tested. The reason for writing this blog is to practice the loop control language, functions, positional parameters, local variables, and function parameter calls, as well as calls between functions, as well as parameters for obtaining user options and options.Note: The script options and the script options parameter get method use getopt and make further judgments, consult the

pre-Class review : To find the sum of divisible by 3 divisible by 200# !/bin/bash -Isum= 0 for with {1..200};d o if [$[$i%3]-eq 0]; then let Su M+="Thesum is: $sum"Bash's knowledge points :Conditional testing: Making a logical operation on a condition　　　　　　　　　　　　with : Condition 1 Condition 2　　　　　　　　　　　　or : Condition 1 | | condition 2　　　　　　　　　　　non- :! Conditions　　　　　　example :#userName =root#id $userName echo "userName exist"If the former fails,

Description : This is a relatively simple bash script editor, but has been tested. The reason for writing this blog is to practice the loop control language, functions, positional parameters, local variables, and function parameter calls, as well as calls between functions, as well as parameters for obtaining user options and options.Note: The script options and the script options parameter get method use getopt and make further judgments, consult the

Bash script skills-trap Command, bash script-trap Share a shell script technique. When you write a shell script, you generally only ensure that the function is available, but the program is not very robust and not robust enough. Most of them are script processing. The built-in trap command can handle unexpected system signals, for example: Trap "rm-f/var/lock/subsys/my_program_lock_file; Exit 0 "1 2 9 15

Set bash options with built-in set and SHOPT commandsThe set command can be used to customize the shell environment, using the option "O" to turn options on or off. For example, open the options: Set-o option, close the Select item: Set +O option.For example, to open the VI Interactive command-line edit, the following: [Email protected] ~]#Set-o#查看当前设置情况Allexport offBraceexpand onEmacs onErrexit offErrtrace offFunctrace offHashall onHiste

In Windows 3.02 64-bit system, when cygwin is used to run the liunux program, the following error occurs: Bash-$: The reason is: In the 64-bit operating system, the 32 program and the 64-bit program read the location registry key, in the 64-bit Registry Editor, HKEY_LOCAL_MACHINE \ SOFTWARE corresponds to the registry key of the 64-bit program, and the 32-bit registry key is mapped to HKEY_LOCAL_MACHINE \ SOFTWARE \ wow6432node. If both versions are r

Bash array, bashBash only supports one-dimensional arrays. And the array subscript starts from 0.Assign values to Arrays:Array = (1 4 7 2 5 8) # use space as the delimiter and () as the arrayStr = "this is test string"Str_arr = ($ str); # separated by spaces by defaultArray traversal:For val in str_arr [*]; do echo $ val; doneFor file in 'LS'; do echo $ file; doneNumber of array elements: $ {# array}For example, each character in a string is split int

$filename/etc/sysconfig/network-scripts[[email protected] Network-scripts] #将第一次出现的小写s替换成大写的S [[email protected] network-scripts]# echo ${filename/s/s}/etc/sysconfig/ Network-scripts[[email protected] network-scripts] #将所有的小写s替换成大写的S [[email protected] network-scripts]# echo ${ Filename//s/s}/etc/sysconfig/network-scripts[[email protected] network-scripts]# Summary:/match/ Value: Replace the first occurrence of match with Value//match/value: Replaces all match with value Operators for

************************************************************************* * * * Original:blog.csdn.net/clark_xu Xu Changliang's Column************************************************************************? time to read the file#!/bin/bashFor file in ' Ls/root 'DoStat $file >1.txtSed-n "7p" 1.txt>2.txtUsetime= awk-f ":" ' {print $2.txt} 'echo "Time=" $file $usetimeDone? reads each line of the file while statement. Cat Afile | While Read onelineDoEcho $onelineDone? reads each line of the file