Shell Script Formatting Alignment

How can I get each line in a shell script to align with the echo displayed in the terminal?

echo “\t***” echo “\t*” try it!

Shell Programming (Mastering Linux Command Line Tools)

Shell programming is a scripting programming language, which is a command line interpreter used in Linux systems to execute commands and script files.Shell programming helps users automate a variety of tasks, thus increasing efficiency and productivity. In this article, we will describe how to use Linux command line tools for Shell programming.

Setting up the development environment

Before we start Shell programming, we need to set up the development environment. First, we need to open a terminal window, which can be done by clicking the terminal icon on the desktop or using the shortcut Ctrl+Alt+T. Next, we need to create a new Shell script file, which can be done by typing the following command in the terminal:

“`

$touchmyscript.sh

“`

This command will create an empty file named myscript.sh. Now we can edit this file using any text editor.

Basic Syntax of Shell Scripts

The syntax of Shell scripts is similar to that of other programming languages, including variables, conditional statements, looping structures, and so on. Here are some basic Shell script syntax:

Variables

In Shell scripts, we can use variables to store values. Variables can be defined using the following syntax:

“`

variable_name=value

“`

For example, the following code will define a variable named “name” and set it to “John”:

“`

name=John

“`

Conditional Statements

Conditional statements are used to execute different chunks of code based on conditions. Here is an example of a simple if statement:

“`

if[$name==”John”]

then

echo “HelloJohn”

fi

“`

In the above code, if the variable “name” is equal to “John”, then “HelloJohn” will be printed.

Loop constructs

Loop constructs are used to execute a piece of code repeatedly. Here is an example of a simple for loop:

“`

foriin12345

do

echo$i

done

“`

In the above code, the loop will be executed 5 times and will print in each iteration the variable “i” value in each iteration.

Commonly Used Linux Command Line Tools

When programming in Shell, we need to use some common Linux command line tools. Here are some common commands:

echo

The echo command is used to print text in the terminal. Here is an example:

“`

echo “HelloWorld”

“`

In the above code, “HelloWorld” will be printed.

grep

The grep command is used to search for text in a file. Here is an example:

“`

grep “hello” myfile.txt

“`

In the above code, the text “hello” will be searched in the file named myfile.txt.

sed

The sed command is used to find and replace text in a file. Here is an example:

“`

sed’s/old_text/new_text/g’myfile.txt

“`

In the above code, all the old text will be searched for in the file named myfile.txt and replaced with new text.

Example Shell Script

The following is an example Shell script that uses variables, conditional statements, and a loop structure to perform a number of tasks:

“`

! /bin/bash

Definevariables

name=”John”

age=25

Printgreetingmessage

echo “Hello$name,youare$ageyearsold “

Checkifageisgreaterthan18

if[$age-gt18]

then

echo “Youareanalt”

else

echo “Youareaminor”

Printgreetingmessage

Printgreetingmessage

Echo “Hello$name,youare$ageyearsold. >fi

Loopthroughnumbers1to5

foriin12345

do

echo$i

done

In the above code, the greeting message will be printed, checking if the age is greater than 18 and loop to print the numbers 1 through 5.

Explain printf'%20s%3s%-s\n' shell script below, please don’t find and paste a big paragraph on the internet

printf’%20s%3s%-s\n’ prints the three parameters in different formats

Format 1 string with at least 20 positions, not enough for 20 to fill in the blanks on the right

Format 2 minimum 3-position string, not enough 3 right fill in the blank

Format 3 left-aligned string

Parameter analysis

“Team1has” string

“$(expr$(ls$dir1|wc-l)-1)’ lists the number of files or directories in the dir1 directory, and then does -1 counting. number of files or directories in the dir1 directory, then do the -1 arithmetic operation to get the result

“files” string

How to format a file with json extension and save the file using shell or python script, help

Don’t know which version of python you are using

I am using python3 which can deal with json files with Chinese characters

Read and write json files: http://python3- cookbook.readthedocs.org/zh_CN/latest/c06/p02_read-write_json_data.html

First importjson

load()loads()

mp()mps()

I. From file:

json to Python data structure: json.load

fo=open(‘data.json’,’r’)

data=json.load(fo)

python data structure to json: json.mp

fo=open(‘data.json’,’r’)

json.mp(data,fo)

Two, python string and json convert each other:

json_str=json.mps(data)

data=json. loads(json_str)

Three, json formatted output:

1, formatted print print

2, formatted output

There are also a number of options that are useful when encoding JSON. If you want nice formatted strings followed by output, you can use the indent parameter of json.mps().

It will make the output similar in effect to the print() function. For example:

print(json.mps(data,indent=4))

fo=open(‘data.json’,’r’)

json.mp(data,fo,indent=4)

Four, with the Chinese json conversion:

jsondata=json.mps(dics,ensure_ascii=False,indent=4)

In the mps method, add the parameter ensure_ascii=False, you can make the Chinese in the dic to convert normally

2. If the python data has both ordinary characters, and Unicode strings, the data can be converted to Chinese. Unicode strings, the above method will not work, but also add encode(‘utf-8’)

Manually convert to utf-8 encoding

jsondata=json.mps(dics,ensure_ascii=False,indent=4).encode(‘ utf-8’)

Shell Programming (Quick Start and Hands-On Tips)

Shell programming is a way of writing scripts that allow the user to execute a series of commands from the command line.A shell is a command line interpreter that interprets commands entered by the user and translates them into a language that the computer understands.Shell programming is a script programming language that uses Shell scripts to write programs.

Why Learn Shell Programming

Shell programming is a very useful skill that can help you automate tasks on a Unix or Linux system.Shell programming allows you to write simple scripts to perform repetitive tasks, which can save a great deal of time and effort.Shell programming also allows you to write efficient scripts to work with data and files, which can be very useful for data analysis and processing.

Basics of Shell Programming

The basics of Shell programming include the Shell scripting language, variables, conditional statements, looping statements, functions, and arrays.

Shell Scripting Language

The Shell Scripting Language is an interpreted language that does not require a compiler, but is executed directly from the command line.Shell scripts usually end with a .sh extension, such as script.sh. The Shell Scripting Language has many commands and operators available to help you with a variety of tasks.

Variables

In Shell programming, variables are a way to store values. Variables can store various types of data, including numbers, strings, and arrays. In Shell programming, variables are often referenced using the $ symbol, such as $variable.The value of a variable can be set by an assignment statement, such as variable=”hello”.

Conditional Statements

Conditional statements are a way of executing different commands based on conditions. In Shell programming, conditional statements are usually implemented using the if-then-else construct. For example, if the variable x is equal to 1, the following code can be used:

if[$x-eq1]

then

echo “xisequalto1”

else

echo “xisnotequalto1”

fi

loop statement

A looping statement is a way of repeating a command. In Shell programming, loop statements are usually implemented using a for or while structure. For example, the following code will print the numbers 1 through 10:

foriin{1..10}

do

echo$i

done

Functions

Functions are a way of encapsulating a set of commands together. In Shell programming, functions are usually defined using a function name and a list of arguments. For example, the following code defines a function named hello:

hello(){

echo “Hello,$1!”

}

The function can be called using the following code:

hello “world”

array

An array is a way to store multiple values. In Shell programming, arrays are often defined and referenced using parentheses. For example, the following code defines an array called fruits:

fruits=(“apple” “banana” “orange”)

The elements of this array can be referenced using the following code:

echo${fruits[0]}犑 Blossom Carp Apple

Shell Programming Hands-On Tips

Besides the basics, here are some Shell programming hands-on tips that can help you get better at using Shell programming.

Command Line Parameters

Command Line Parameters are the parameters that are passed to a Shell script on the command line. In Shell programming, you can use variables such as $1, $2, etc. to refer to these parameters. For example, the following code will print the first parameter passed to the script:

echo$1

Redirection and piping

Redirection and piping are two ways to redirect the output of a command to a file or other command. In Shell programming, you can use the > and > > operators to redirect output to a file. For example, the following code will redirect the output of a command to a file:

ls>files.txt

Command substitution

Command substitution is a way to use the output of a command as a variable value. In Shell programming, command substitution can be implemented using the $() or “ operators. For example, the following code takes the output of a command as a variable value:

files=$(ls)

Error Handling

Error handling is a way of dealing with command execution errors. In Shell programming, you can use the set-e command to set a script to exit on an error. For example, the following code would set a script to exit on an error:

set-e

Debugging

Debugging is a way of finding and fixing script errors. In Shell programming, you can use the set-x command to set a script to output the results of the execution of each command. For example, the following code would set the script to output the results of each command’s execution:

set-x