🧠 How to Use Demasko Bot for Anonymous Advice & Support

Dereje Desta — Sun, 01 Jun 2025 09:37:33 +0000

Demasko Bot is a Telegram-based support bot where you can anonymously share your feelings and receive guidance from professionals. Here’s how to use it:

✨ Step 1: Start the Bot

Click this link: http://t.me/demasko_bot
Tap the Start button to begin.

🔧 Step 2: Choose an Option

After starting, you'll see two main options:

❤️ Share your feelings: Ask your personal or emotional questions anonymously.
📃 Past conversations: View your previous chats and responses.

🧐 Step 3: Ask a Question

Tap Share your feelings.
Type out your question in the chat box.
Hit Send.

Your question will be:

Saved securely.
Forwarded to moderators.
Answered anonymously.

You'll be notified when a response is available.

📂 Step 4: View Past Conversations

Tap Past conversations.
You’ll see a list of previous questions (1–3 per page).
Reply with a number (e.g. 1) to view the answer.
Tap Next to load more questions.

🔔 Step 5: View Published Answers in the Channel

If you’re a member of the Demasko Telegram Channel:

You’ll see selected Q&As chosen by admins.
Tap the button under the message to view full answers instantly.

These are handpicked for their usefulness and relevance.

🚀 Start Now

Join Demasko Bot and take the first step toward mental clarity.

You're not alone — we're here to listen.

How Shell Executes `ls -l *.c`

Dereje Desta — Tue, 02 Nov 2021 10:28:33 +0000

In this post, we'll talk about how the shell executes the command ls -l *.c. Moreover, we'll also discuss how it is implemented under the hood.

We strongly advise you to have at least fundamental knowledge of C programming language and Linux system programming before you continue.

Note that we skipped error checks and memory management for brevity. Refer to the project implemention.

When we open a shell(user perspective) it prompts us to enter a line of command and when we enter the command it executes our command and prompts us to enter another command.

But there is more to this story. The following are simplified versions of the steps the shell takes.

1. Getline

The shell prints the prompt and waits for input. Let us assume we entered ls -l *.c. This is performed using getline().

 while(1) {
    char *line = NULL;
    size_t len = 0, nline;
    printf("$ ");
    nline = getline(&line, &len, stdin);
    if(nline == -1) return 0;
    // continues here
}

2. Tokenize

Then The shell splits this line of command into tokens. In our case ls, -l and *.c. this uses strtok(command, DELIM) where DELIM is string consisting whitespaces character(spaces, tabs and etc.).

// continued
const char *DELIM =  " \t\a\r"
token = strtok(line, DELIM);
while(token != NULL) {
    tokens[pos++] = strup(token); // push to array of strings
    token = strtok(NULL, DELIM);
}

3. Expansion

After that the shell looks for expansion in our case token *.c matches every file ending in .c. So tokens will become:

tokens = {"ls", "-l", "main.c", "util.c", "test.c"};

4. Alias

The shell checks if the first token is aliased. if it is it replaces it with the original expanded version. In our case ls is aliased to ls --color=tty.

ls: aliased to ls --color=tty
/usr/bin/ls
/bin/ls

5. Builtins

Then checks if the command is builtin(like exit, cd, help ... etc). ls is not builtin command.

6. PATH

If the command is not builtin command it searches the command in the PATH environmental variable. ls is found in path /bin/ls.

7. New Process

After that Create a new process using syscall fork().

int status;
pid_t child_pid = fork();
if (child_pid == -1)
    return (1);

if (child_pid == 0) // if this is child process execute
{
    if (execve(tokens[0], tokens, __environ) == -1)
        return (1);
} else // if it is parent wait for child
    wait(&status);

8. Execution

Finally, it executes it. It uses execve(tokens[0], tokens, env) system call. See step 7. and continue at step 1 again.

Conclusion

This is just a simple illustration of how shell goes on executing commands like ls -l *.c. But nowadays shells have evolved to do many complex tasks like history, conditional statements, loops, and any other things programming languages support. It was quite a journey learning shell and we do believe you can benefit by implementing those concepts in yourself. You can find our implementation in C here. Thanks 👍

Forem: Dereje Desta