Mastering the Art of Linux with Complete Redirection Techniques（linux全部重定向）

Mastering the Art of Linux with Complete Redirection Techniques

Linux is an open-source operating system that offers a variety of benefits to users, including enhanced security, stability, and flexibility. However, it can also be a complex and challenging system to navigate, especially for new users. One of the most useful techniques for mastering Linux is the use of redirection, which allows you to redirect input and output from one command or file to another. In this article, we’ll explore the different types of redirection and provide examples of how to use them effectively.

Types of Redirection in Linux

There are three main types of redirection that can be used in Linux:

1. Standard Input Redirection – this allows you to redirect input from a file or command directly to a program or script. This can be done using the “

For example, let’s say you have a file called “numbers.txt” that contains a list of numbers. You can use standard input redirection to feed these numbers into a script that will calculate the sum:

#!/bin/bash
# sum.sh - script to sum a list of numbers

while read -r line; do
   sum=$((sum + line))
done

echo "The sum is: $sum"

To use standard input redirection, simply run the following command:

$ ./sum.sh 

2. Standard Output Redirection – this allows you to redirect the output of a command or script to a file or another command. This can be done using the “>” symbol, followed by the file name or command.

For example, suppose you have a script that generates a list of files in a directory. You can use standard output redirection to save this list to a file called “files.txt”:

#!/bin/bash
# list_files.sh - script to list files in a directory

FILES=$(ls)

echo "$FILES" > files.txt

To use standard output redirection, simply run the following command:

$ ./list_files.sh

This will generate a file called “files.txt” that contains the list of files in the directory.

3. Standard Error Redirection – this allows you to redirect error messages generated by a command or script to a file or another command. This can be done using the “2>” symbol, followed by the file name or command.

For example, suppose you have a script that attempts to open a file that does not exist. You can use standard error redirection to save the error message to a file called “errors.txt”:

#!/bin/bash
# open_file.sh - script to open a file

if [ -f my_file.txt ]; then
   cat my_file.txt
else
   echo "Error: File not found" 2> errors.txt
fi

To use standard error redirection, simply run the following command:

$ ./open_file.sh

This will generate a file called “errors.txt” that contains the error message generated by the script.

Conclusion

Redirection is a powerful technique that can help you master the art of Linux. By redirecting input, output, and error messages, you can accomplish a wide range of tasks more efficiently and effectively. Whether you’re a new user or an experienced pro, mastering redirection will take your Linux skills to the next level.