The wide range of uses of the Linux read command: Explore multiple application scenarios

Linux system is an open source operating system with powerful functions and flexibility, and the read command is one of the very practical commands. This article will explore various application scenarios of the Linux read command and provide specific code examples to help readers better understand and use this command.

1. Read user input

The most common use of the read command is to read user input. The user can enter content through the keyboard, and the read command can save these inputs to a variable and then process them in the script.

#!/bin/bash

echo "请输入您的姓名："
read name
echo "您好，$name！"

After running the above script, the user will be prompted to enter a name. After the user enters the name, the script will output a "Hello, name!" message.

2. Read command output

The read command can also be used in conjunction with pipes to read the output of another command and save it to a variable.

#!/bin/bash

files=$(ls)
echo "当前目录下的文件有："
echo "$files"

In the above script, the ls command is used to list the file list in the current directory, then save these files to the variable files, and finally output the file list.

3. Read the file content

The read command can also be used to read the file content line by line and process it.

#!/bin/bash

filename="example.txt"

while IFS= read -r line
do
    echo "内容： $line"
done < "$filename"

The above script will read the contents of the example.txt file line by line and output the contents of each line.

4. Read multiple inputs

The read command can also read multiple inputs at one time and save them to multiple variables.

#!/bin/bash

echo "请输入姓名和年龄："
read name age
echo "$name 的年龄是 $age 岁"

The above script will prompt the user to enter their name and age, then save these two inputs into two variables, name and age, and finally output the values ​​of these two variables.

5. Read with timeout function

The read command can also set a timeout. If the user does not input after the specified time, it will timeout and exit.

#!/bin/bash

read -t 5 -p "请输入您的选择（5秒内）："

if [ -z "$REPLY" ]; then
    echo "超时"
else
    echo "您选择了：$REPLY"
fi

A 5-second timeout is set in the above script. If the user does not input within 5 seconds, "timeout" will be prompted, otherwise the user's choice will be output.

In general, the read command in Linux systems has a wide range of application scenarios and can be used for reading user input, reading command output, reading file content, etc. Through the specific code examples provided in this article, I hope readers can better grasp and apply this practical command.

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