> For the complete documentation index, see [llms.txt](https://notes.anir0y.in/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://notes.anir0y.in/linux/system-information.md).

# System Information

Since we will be working with many different Linux systems, we need to learn the structure and the information about the system, its processes, network configurations, users, directories, user settings, and the corresponding parameters.

Here is a list of the necessary tools that will help us get the above information. Most of them are installed by default.

| **Command** | **Description**                                                                                                                    |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| `whoami`    | Displays current username.                                                                                                         |
| `id`        | Returns users identity                                                                                                             |
| `hostname`  | Sets or prints the name of current host system.                                                                                    |
| `uname`     | Prints operating system name.                                                                                                      |
| `pwd`       | Returns working directory name.                                                                                                    |
| `ifconfig`  | The ifconfig utility is used to assign or to view an address to a network interface and/or configure network interface parameters. |
| `ip`        | Ip is a utility to show or manipulate routing, network devices, interfaces and tunnels.                                            |
| `netstat`   | Shows network status.                                                                                                              |
| `ss`        | Another utility to investigate sockets.                                                                                            |
| `ps`        | Shows process status.                                                                                                              |
| `who`       | Displays who is logged in.                                                                                                         |
| `env`       | Prints environment or sets and executes command.                                                                                   |
| `lsblk`     | Lists block devices.                                                                                                               |
| `lsusb`     | Lists USB devices                                                                                                                  |
| `lsof`      | Lists opened files.                                                                                                                |
| `lspci`     | Lists PCI devices.                                                                                                                 |

Let us look at a few examples.

**Whoami**

```
anir0y@arishti[/lab]$ whoami

cry0l1t3
```

**Id**

```
anir0y@arishti[/lab]$ id
uid=1000(cry0l1t3) gid=1000(cry0l1t3) groups=1000(cry0l1t3),1337(hackthebox),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),116(lpadmin),126(sambashare)
```

**Uname**

```
anir0y@arishti[/lab]$ uname -a

Linux box 4.15.0-99-generic #100-Ubuntu SMP Wed Apr 22 20:32:56 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
```

It is highly recommended to study the commands and understand what they are for and what information they can provide. This information is not only used for working with Linux. However, it will also be used later to discover vulnerabilities and misconfigurations on the Linux system that may contribute to privilege escalation.