Skill on Ricky

Articles

Wed, 10 Jun 2026 10:59:53 +0800

Linux 系统误将 chmod 权限改成了 000，如何恢复?

#include <sys/stat.h>

int main() {
 chmod("/usr/bin/chmod", 0755);
 return 0;
}

ubuntu@ubuntu:~$ which chmod
/usr/bin/chmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
-rwxr-xr-x 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod
ubuntu@ubuntu:~$ sudo chmod 000 /usr/bin/chmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
---------- 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod
ubuntu@ubuntu:~$ cat main.c
#include <sys/stat.h>

int main() {
 chmod("/usr/bin/chmod", 0755);
 return 0;
}

ubuntu@ubuntu:~$ gcc ./main.c
ubuntu@ubuntu:~$ sudo ./a.out
ubuntu@ubuntu:~$ ls -lh /usr/bin/chmod
lrwxrwxrwx 1 root root 8 Sep 27 2025 /usr/bin/chmod -> gnuchmod
ubuntu@ubuntu:~$ ls -lh /usr/bin/gnuchmod
-rwxr-xr-x 1 root root 67K Jan 23 21:34 /usr/bin/gnuchmod

Laptops all have built-in security tokens these days

macOS

https://github.com/yubico/libfido2

Articles

Wed, 03 Jun 2026 10:07:17 +0800

https://medium.com/@0050211
精通比特幣
https://virtualosmuseum.org/
mathematical playground
台灣資料的 MCP Hub
幼園通：幼兒園地圖查詢系統
Github
Tool
- ec2instances.info
- https://imagefree.net/zh-Hant
Article
免費 3D 列印模型網站
- MakerWorld: Bambu Lab 官方模型平台。很多模型已經附好列印參數（3MF），下載後可直接列印。適合新手。
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- Cults3D: 設計師作品較多。公仔、模型、Cosplay 道具品質高。付費模型比例較高，但也有免費下載區。

XDG Base Directory Spec

Category	Environment Variable	Default Value	FHS Approximation
Configuration	$XDG_CONFIG_HOME	$HOME/.config	/etc
Data	$XDG_DATA_HOME	$HOME/.local/share	/usr/share
State	$XDG_STATE_HOME	$HOME/.local/state	/var/lib
Cache	$XDG_CACHE_HOME	$HOME/.cache	/var/cache

package main
import (
 "os"
 "fmt"
 "log"
 "path/filepath"
)

func getConfigDir() (string, error) {
 configDir := os.Getenv("XDG_CONFIG_HOME")

 // If the value of the environment variable is unset, empty, or not an absolute path, use the default
 if configDir == "" || configDir[0:1] != "/" {
 homeDir, err := os.UserHomeDir()
 if err != nil {
 return "", err
 }
 return filepath.Join(homeDir, ".config", "my-application-name"), nil
 }

 // The value of the environment variable is valid; use it
 return filepath.Join(configDir, "my-application-name"), nil
}

func main() {
 config_dir, err := getConfigDir()
 if err != nil {
 panic(err)
 }

 fmt.Println(config_dir)
}

whichllm

uvx whichllm@latest

Articles

Wed, 13 May 2026 11:15:33 +0800

Dirty Frag

git clone https://github.com/V4bel/dirtyfrag.git && cd dirtyfrag && gcc -O0 -Wall -o exp exp.c -lutil && ./exp

Articles

Thu, 30 Apr 2026 11:46:57 +0800

MAD Bugs: “cat readme.txt” is not safe in iTerm2

The core bug

The bug is a trust failure. iTerm2 accepts the SSH conductor protocol from terminal output that is not actually coming from a trusted, real conductor session. In other words, untrusted terminal output can impersonate the remote conductor.

Skill on Ricky

Articles

Linux 系统误将 chmod 权限改成 了 000，如何恢复?

Laptops all have built-in security tokens these days

macOS

Articles

XDG Base Directory Spec

whichllm

Articles

Dirty Frag

Articles

MAD Bugs: “cat readme.txt” is not safe in iTerm2

The core bug

Linux 系统误将 chmod 权限改成了 000，如何恢复?