bash history

Fun Bash Script: numerical calculation, bash script Numerical Calculation 6th articles The mathematical operations in Bash are not as simple as other languages, because Bash treats all variables as strings, so a = 1 + 2, a is not equal to 3, but equal to string 1 + 2. There are several solutions to solve this problem.

Bash introduction, bash Vulnerability Bash is not just a command parsing program. It has a programming language, which allows you to write shell scripts to complete a variety of tasks that cannot be completed by using ready-made commands, bash scripts can use if-then-elif-else-fi statements, for statements, while stat

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

Fun Bash Script: select the structure of if, bash script Almost all programming languages have the concept of process control, that is, order structure, selection structure and loop structure. The selected structure is also called the branch structure, such asIfAndSwitchStatement.If condition I have already discussed the use of the test Expression and Its Simplified [] Operator. These judgment statements ca

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

Iii. Command HistoryBash has absorbed a lot of essence from the Korn shell and the C shell, one of which formally holds the feature of a cached copy of the executed command, which we call the "command history" feature.Why should we use the command history feature?After each user login succeeds, especially after login with file interface such as bash, all operatio

strings that are not spoken (Process substitution and History commands are expanded). When you're programming with bash scripting, it's enough to understand how the 7 types of strings are generated. When you use the Bash command line interactively, you also need to know the history command to expand, skilled use of th

BASH command and usage summary, bash usage Summary I need to write a Linux script in my recent work and use a lot of BASH commands. To avoid forgetting it later, I will write them down here one by one. It may be messy. Just take a look. If something is wrong, you are welcome to correct it. 1, export VAR =... This command runs in Shell to make the script that runs

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

Learning bash notes-input and output, bash hide output1. I/O redirection The I/O redirection is as follows: Cmd1 | cmd2: pipeline that receives the standard output of cmd1 as the standard input of cmd2. > File: redirects standard output to file. > File: redirects the standard output to file. If the file exists, it is appended > | File: Even if noclobber is set, the standard output is still fo

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 internal variable learning and Bash variable learning $ SECONDS variable --------- number of SECONDS after the script has been run. Script instance: 1 #!/bin/bash - 2 #=========================================================================================== 3 # 4 # 5 # FILE:seconds.sh 6 #

Linux new user with ssh remote login display-bash-4.1 $, ssh-bash-4.1 There are many methods on Baidu, most of which are in the form of adding PS1 code in. bash_profile, and then logging on to the account again... This method is difficult to achieve the desired results. The root cause of this problem is the lack of Shell environment! [Root @ localhost ~] Su-papi1Last login: Wed Jan 24 04:11:41 EST 2018

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

Bash saves the history of commands used. The history of these commands is stored in the. bash_history file of the user's main directory. Introduction Bash saves the history of commands used. The history of these commands is stored

Linux Bash Shell learning notes, bash learning notes Parameter extension: 1. The parameter referenced by the name is called a variable.2. Parameters referenced by numbers are called positional parameters.3. Parameters referenced by a specific symbol have special meanings and purposes, and are referred to as Bash's special internal variable reference. Basic Parameter extension:Character $ will guide paramete

Bash basics man manual and bash basics manBash basics man Manual Penetration tests based on Android devices are implemented through various terminals. Therefore, it is particularly important to master Shell-related operations. Bash is a Unix Shell program written for GNU. This document selects the Kali Linux penetration test tutorial Based on Android devices. It

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