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151 lines
5.5 KiB
Markdown
151 lines
5.5 KiB
Markdown
# Linux Environment Variables
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Support HackTricks</summary>
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* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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## Global variables
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The global variables **will be** inherited by **child processes**.
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You can create a global variable for your current session doing:
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```bash
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export MYGLOBAL="hello world"
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echo $MYGLOBAL #Prints: hello world
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```
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This variable will be accessible by your current sessions and its child processes.
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You can **remove** a variable doing:
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```bash
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unset MYGLOBAL
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```
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## Local variables
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The **local variables** can only be **accessed** by the **current shell/script**.
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```bash
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LOCAL="my local"
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echo $LOCAL
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unset LOCAL
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```
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## List current variables
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```bash
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set
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env
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printenv
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cat /proc/$$/environ
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cat /proc/`python -c "import os; print(os.getppid())"`/environ
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```
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## Common variables
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From: [https://geek-university.com/linux/common-environment-variables/](https://geek-university.com/linux/common-environment-variables/)
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* **DISPLAY** – the display used by **X**. This variable is usually set to **:0.0**, which means the first display on the current computer.
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* **EDITOR** – the user’s preferred text editor.
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* **HISTFILESIZE** – the maximum number of lines contained in the history file.
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* **HISTSIZE** – Number of lines added to the history file when the user finish his session
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* **HOME** – your home directory.
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* **HOSTNAME** – the hostname of the computer.
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* **LANG** – your current language.
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* **MAIL** – the location of the user’s mail spool. Usually **/var/spool/mail/USER**.
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* **MANPATH** – the list of directories to search for manual pages.
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* **OSTYPE** – the type of operating system.
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* **PS1** – the default prompt in bash.
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* **PATH** – stores the path of all the directories which holds binary files you want to execute just by specifying the name of the file and not by relative or absolute path.
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* **PWD** – the current working directory.
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* **SHELL** – the path to the current command shell (for example, **/bin/bash**).
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* **TERM** – the current terminal type (for example, **xterm**).
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* **TZ** – your time zone.
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* **USER** – your current username.
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## Interesting variables for hacking
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### **HISTFILESIZE**
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Change the **value of this variable to 0**, so when you **end your session** the **history file** (\~/.bash\_history) **will be deleted**.
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```bash
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export HISTFILESIZE=0
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```
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### **HISTSIZE**
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Change the **value of this variable to 0**, so when you **end your session** any command will be added to the **history file** (\~/.bash\_history).
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```bash
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export HISTSIZE=0
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```
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### http\_proxy & https\_proxy
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The processes will use the **proxy** declared here to connect to internet through **http or https**.
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```bash
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export http_proxy="http://10.10.10.10:8080"
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export https_proxy="http://10.10.10.10:8080"
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```
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### SSL\_CERT\_FILE & SSL\_CERT\_DIR
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The processes will trust the certificates indicated in **these env variables**.
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```bash
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export SSL_CERT_FILE=/path/to/ca-bundle.pem
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export SSL_CERT_DIR=/path/to/ca-certificates
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```
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### PS1
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Change how your prompt looks.
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[**This is an example**](https://gist.github.com/carlospolop/43f7cd50f3deea972439af3222b68808)
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Root:
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.png>)
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Regular user:
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.png>)
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One, two and three backgrounded jobs:
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.png>)
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One background job, one stopped and last command didn't finish correctly:
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.png>)
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
|
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<details>
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<summary>Support HackTricks</summary>
|
||
|
||
* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
|
||
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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