The Linux alias command is used to set command aliases, allowing users to define their own command shortcuts. It enables you to execute commands in a simpler and more memorable way without having to type the full command each time. If you simply enter alias, it will list all currently set aliases. The effect of … Read more
This article mentions the <span>trap</span> command in the Linux Shell script debugging advanced (trap bashdb). Here we will further introduce the <span>trap</span> command. <span>trap</span> is a powerful command in the shell used to capture and handle <span>signals</span>. It allows you to respond to system signals during script execution, achieving <span>graceful exits</span>, <span>resource cleanup</span>, and <span>debugging</span> … Read more
1. Command Introduction and Principles 1.1 Introduction ZIP is a powerful cross-platform compression tool used to create ZIP format compressed files. Unlike GZIP, ZIP can directly compress entire directories and multiple files, while fully preserving file permissions, timestamps, and other metadata in the compressed file. This makes ZIP very practical for file compression and archiving … Read more
Detailed Explanation of the Linux sed Tool 1. Introduction to sed Those who frequently use Linux shell scripts will certainly notice the high frequency of the sed tool. So, what is sed used for, and what can it do? As one of the “three musketeers” of Linux, sed originated from ed and is a stream … Read more
<span>Shell</span> scripts are indeed prone to errors during development, especially for beginners who may feel overwhelmed. In previous articles, I introduced some debugging techniques and tools, and today I will introduce a <span>static code analysis tool</span> for Shell: <span>ShellCheck</span>, an open-source project with 38.5k[1] stars on Github[1]. As an open-source static code analysis tool, ShellCheck … Read more
There are two ways to specify debugging options. One is to specify options when executing the <span>bash</span> command: # -x prints commands and their arguments during execution bash -x debug.sh The other is to set it in the <span>bash</span> script using the built-in command <span>set</span>: #!/bin/bash set -x # Enable debugging # Here is some … Read more
In the shell environment, the following methods are supported for mathematical or logical operations. Using the expr command to perform mathematical or logical operations directly, such as<span><span>expr 2 + 2</span></span>. Using the bc command, data is piped into the bc command for calculations, for example<span><span>echo "scale=4; 3.44/5" | bc</span></span>. Using the<span><span>$ and $[operation]</span></span> format brackets … Read more
1. Command Introduction and Principles 1.1 Introduction The find command is the most powerful and flexible file search tool in the Linux system, capable of recursively searching for files in a directory tree and filtering based on various conditions. It is not only a file search tool but can also perform various operations on the … Read more
In shell syntax, a function is a encapsulation of command line expressions that can be called. Similar to C language, the format of a shell function is as follows. # Function definitionfunction [func_name]{ # Function body}# The function name can optionally be followed by (), which has no actual significance. # Examplefunction func_test{ echo "test"}# … Read more
One day, I suddenly wanted to implement a Redis client using Bash, adhering to the principle of <span>not reinventing the wheel</span>, and discovered an open-source library redi.sh[1]. As a client, it is essential to establish a TCP connection with the server. Driven by curiosity, I studied its source code: exec {FD}<> /dev/tcp/"$REDIS_HOST"/"$REDIS_PORT" As shown above, … Read more