> For the complete documentation index, see [llms.txt](https://42-guide.gitbook.io/42-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://42-guide.gitbook.io/42-guide/piscine-life/shell00/testshell00.md).
# testShell00
**Objective**
The goal of this exercise is to create a file named `testShell00` with specific **file permissions** and **attributes**. After creating the file, you need to package it into a `.tar` archive for submission.
The file should have the following attributes when viewed with the `ls -l` command:
```
total 1
-r--r--x--x 1 XX XX 40 Jun 1 23:42 testShell00
```
* **File permissions**: `r--r--x--x` (read-only for owner and group, execute-only for others).
* **Size**: 40 bytes.
* **Timestamp**: June 1st, 23:42 (or any valid date/time).
***
**What You Need to Do**
1. Create a file named `testShell00`.
2. Set the file permissions to `r--r--x--x`.
3. Set the file size to 40 bytes.
4. Set the file's timestamp to a specific date and time (e.g., June 1st, 23:42).
5. Package the file into a `.tar` archive named `testShell00.tar`.
***
**Step-by-Step Explanation**
1. **Create the File**:
* Use the `touch` command to create an empty file:
```bash
touch testShell00
```
2. **Set File Permissions**:
* Use the `chmod` command to set the file permissions to `r--r--x--x`.
* The permission code for `r--r--x--x` is `445` (read `4`, read `4`, execute `1`).
```bash
chmod 445 testShell00
```
* Alternatively, you can use symbolic notation:#
```bash
chmod u=r,g=r,o=x testShell00
```
3. **Set the File Size to 40 Bytes**:
* You can use the `echo` command to add content to the file until it reaches 40 bytes.
* For example, add 40 characters to the file:
```bash
echo "This file is exactly 40 bytes long." > testShell00
```
* Verify the file size using the `ls -l` command:
```bash
ls -l testShell00
```
The output should show a size of 40 bytes.
4. **Set the File's Timestamp**:
* Use the `touch` command with the `-t` option to set a specific timestamp.
* The format for the timestamp is `YYYYMMDDHHMM.SS`.
* For example, to set the timestamp to June 1st, 23:42:
```bash
touch -t 202306012342 testShell00
```
* Verify the timestamp using `ls -l`:
```bash
ls -l testShell00
```
5. **Package the File into a `.tar` Archive**:
* Use the `tar` command to create a `.tar` archive:
```bash
tar -cf testShell00.tar testShell00
```
* This creates a file named `testShell00.tar` containing `testShell00`.
***
**Key Concepts to Learn**
1. **File Permissions**:
* File permissions in Unix are divided into three categories: **owner**, **group**, and **others**.
* Permissions are represented as `rwx` (read, write, execute) or as a numeric code (e.g., `755`).
* Use `chmod` to change file permissions.
2. **File Size**:
* The size of a file is determined by its content.
* You can use commands like `echo` or `dd` to create files of specific sizes.
3. **File Timestamp**:
* The `touch` command can be used to modify a file's access and modification timestamps.
* The `-t` option allows you to set a specific timestamp.
4. **Creating `.tar` Archives**:
* The `tar` command is used to create archives (`.tar` files).
* The `-c` option creates a new archive, and the `-f` option specifies the archive's filename.
***
**Resources for Further Learning**
* **File Permissions**:
* [Linux File Permissions](https://linux.die.net/man/1/chmod)
* **File Timestamps**:
* [Touch Command in Linux](https://linux.die.net/man/1/touch)
* **Tar Command**:
* [Tar Command in Linux](https://linux.die.net/man/1/tar)
***
**Final Steps**
1. Create the file:
```bash
touch testShell00
```
2. Set permissions:
```bash
chmod 445 testShell00
```
3. Set the file size to 40 bytes:
```bash
echo "This file is exactly 40 bytes long." > testShell00
```
4. Set the timestamp:
```bash
touch -t 202306012342 testShell00
```
5. Verify the file attributes:
```bash
ls -l testShell00
```
6. Create the `.tar` archive:
```bash
tar -cf testShell00.tar testShell00
```
---
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