Complete introduction and usage of Linux read command

Title: Detailed explanation and usage guide of Linux read command

In Linux system, read command is a very common command, used to read from standard input or file Get the data and assign the data to the variable. Its usage is simple and flexible, and can help users achieve various interactive operations. This article will introduce the syntax, parameters and specific code examples of the read command in detail to help readers better understand and master the command.

1. Read command syntax and parameters

The basic syntax of the read command is as follows:

read [选项] [变量名]

Commonly used options include:

• -p prompt: Specifies the prompt when reading data.
• -r: Prevent the read command from escaping backslash characters.
• -t timeout: Set the timeout in seconds.
• -n nchars: Specifies the number of characters to read.
• -s: Silent mode, user input is not displayed.
• -u fd: Read data from file descriptor fd.

2. Read command example

1. Read user input and assign it to variables:

read -p "请输入您的姓名：" name
echo "您的姓名是：$name"

Running the above code will prompt the user Enter a name, assign the entered value to the variable name, and then output the value of the name.

2. Read multiple data and assign values ​​to multiple variables:

read -p "请输入您的姓名和年龄：" name age
echo "您的姓名是：$name，年龄是：$age"

This code will prompt the user to enter their name and age, and then assign the entered values ​​to Give variables name and age and output their values.

3. Use a loop to read multiple lines of data:

echo "请输入三个喜欢的水果："
count=0
while [ $count -lt 3 ]
do
    read fruit
    echo "您喜欢的水果之一是：$fruit"
    ((count++))
done

This code will loop to prompt the user to enter three favorite fruits, and output each fruit entered by the user in sequence. .

4. Set the timeout:

if read -t 5 -p "请输入您的密码：" password
then
    echo "密码输入成功：$password"
else
    echo "密码输入超时"
fi

This code will wait for the user to enter the password within 5 seconds. If it times out, it will output "Password input timeout", otherwise it will output the user input. password.

3. Summary

Through the above examples, readers can have a deeper understanding of the usage and flexibility of the read command in Linux. The read command is very useful when writing scripts and implementing interactive functions, and can simplify the process of user input data. I hope this article can help readers better master the read command and play its role in practical applications.

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