<a href="https://github.com/orhun/systeroid">
<img align="left" src="assets/systeroid-logo.jpg" width="256">
</a>
#### **`systeroid`** — A more powerful alternative to sysctl(8).
[`sysctl(8)`](https://man7.org/linux/man-pages/man8/sysctl.8.html) is a utility on Unix-like operating systems that is used to read and modify the attributes of the kernel such as its version number, maximum limits, and security settings[\*](https://en.wikipedia.org/wiki/Sysctl). **systeroid** is "_sysctl on steroids_". It can do everything that sysctl does and even more. It provides a safer, more performant, and user-friendly CLI/TUI for managing the kernel parameters at runtime.
<a href="https://github.com/orhun/systeroid/releases">
<img src="https://img.shields.io/github/v/release/orhun/systeroid?style=flat&logo=GitHub%20Actions&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<a href="https://crates.io/crates/systeroid/">
<img src="https://img.shields.io/crates/v/systeroid?style=flat&logo=Rust&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<a href="https://codecov.io/gh/orhun/systeroid">
<img src="https://img.shields.io/codecov/c/gh/orhun/systeroid?style=flat&logo=Codecov&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<br>
<a href="https://github.com/orhun/systeroid/actions?query=workflow%3A%22Continuous+Integration%22">
<img src="https://img.shields.io/github/actions/workflow/status/orhun/systeroid/ci.yml?style=flat&logo=GitHub%20Actions&label=build&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<a href="https://github.com/orhun/systeroid/actions?query=workflow%3A%22Continuous+Deployment%22">
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</a>
<a href="https://hub.docker.com/r/orhunp/systeroid">
<img src="https://img.shields.io/github/actions/workflow/status/orhun/systeroid/docker.yml?style=flat&logo=Docker&label=docker&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<a href="https://docs.rs/systeroid-core/">
<img src="https://img.shields.io/docsrs/systeroid-core?style=flat&logo=Rust&labelColor=000000&color=CECDCB&logoColor=CECDCB">
</a>
<br>
<br>
<br>
**systeroid** is implemented using [procfs](https://en.wikipedia.org/wiki/Procfs) which is the virtual file system that is typically mapped to a mount point named `/proc` at boot time. This means checking the value of some kernel parameter requires opening a file in this virtual filesystem, reading its contents, parsing them, and closing the file. In [Linux](https://en.wikipedia.org/wiki/Linux), these dynamically configurable kernel options are available under `/proc/sys` which contains directories representing the sections of the kernel and readable/writable virtual files. For example, to enable/disable IP forwarding, `1` or `0` could be written in `/proc/sys/net/ipv4/ip_forward` or `systeroid ip_forward=1` command can be used to change the value of the parameter.
<a href="assets/systeroid-demo.gif">
<img src="assets/systeroid-demo.gif" width="800">
</a>
Although **systeroid** does not need the parameter section to be specified explicitly, it is important to know the sections and their areas of impact. Here are the available kernel sections according to the [Linux kernel documentation](https://www.kernel.org/doc/html/latest/admin-guide/sysctl/index.html):
| Section | Path | Description |
| ---------- | ------------------- | ------------------------------------------------------------- |
| **abi** | `/proc/sys/abi/` | execution domains & personalities |
| **fs** | `/proc/sys/fs/` | filesystem settings |
| **kernel** | `/proc/sys/kernel/` | global kernel information / miscellaneous settings |
| **net** | `/proc/sys/net/` | networking settings |
| **sunrpc** | `/proc/sys/sunrpc/` | SUN Remote Procedure Call settings |
| **user** | `/proc/sys/user/` | user namespace limits |
| **vm** | `/proc/sys/vm/` | memory management tuning buffer and cache management settings |
| **dev** | `/proc/sys/dev/` | device specific information |
| **debug** | `/proc/sys/debug/` | - |
---
<!-- vim-markdown-toc GFM -->
- [Requirements](#requirements)
- [Installation](#installation)
- [Cargo](#cargo)
- [Arch Linux](#arch-linux)
- [Binary releases](#binary-releases)
- [Building from source](#building-from-source)
- [Docker](#docker)
- [Images](#images)
- [Usage](#usage)
- [Building](#building)
- [Usage](#usage-1)
- [Options](#options)
- [Examples](#examples)
- [Listing parameters](#listing-parameters)
- [Filtering by section](#filtering-by-section)
- [Displaying values](#displaying-values)
- [Setting values](#setting-values)
- [Loading values from a file](#loading-values-from-a-file)
- [Loading values from the system directories](#loading-values-from-the-system-directories)
- [Searching parameters](#searching-parameters)
- [Showing information about parameters](#showing-information-about-parameters)
- [TUI](#tui)
- [Usage](#usage-2)
- [Key Bindings](#key-bindings)
- [Examples](#examples-1)
- [Launching](#launching)
- [Showing help](#showing-help)
- [Scrolling](#scrolling)
- [Toggling the kernel section](#toggling-the-kernel-section)
- [Searching](#searching)
- [Setting values](#setting-values-1)
- [Saving values](#saving-values)
- [Running commands](#running-commands)
- [Copying to clipboard](#copying-to-clipboard)
- [Changing the colors](#changing-the-colors)
- [Viewing the parameter documentation](#viewing-the-parameter-documentation)
- [Setting the refresh rate](#setting-the-refresh-rate)
- [Configuration](#configuration)
- [Resources](#resources)
- [References](#references)
- [Logo](#logo)
- [Social Links](#social-links)
- [In The Media](#in-the-media)
- [Funding](#funding)
- [Contributing](#contributing)
- [License](#license)
- [Copyright](#copyright)
<!-- vim-markdown-toc -->
## Requirements
- [`Rust`](https://www.rust-lang.org/) (`>=1.64.0`) (see [building from source](#building-from-source))
- [`libxcb`](https://gitlab.freedesktop.org/xorg/lib/libxcb) (for [clipboard support](#copying-to-clipboard))
- [`linux-documentation`](https://www.kernel.org/doc/) (for [viewing the documentation](#viewing-the-parameter-documentation))
To install the runtime dependencies:
- on Arch Linux: `pacman -S libxcb libxkbcommon linux-docs`
- on Debian/Ubuntu: `apt-get install libx11-dev libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev linux-doc`
- on Fedora: `dnf install libX11-devel kernel-doc`
## Installation
<details>
<summary>Packaging status</summary>
[](https://repology.org/project/systeroid/versions)
</details>
### Cargo
**systeroid** is available on [crates.io](https://crates.io/crates/systeroid):
```sh
cargo install systeroid
cargo install systeroid-tui
```
### Arch Linux
**systeroid** can be installed from the [community repository](https://archlinux.org/packages/community/x86_64/systeroid/) using [pacman](https://wiki.archlinux.org/title/Pacman):
```sh
pacman -S systeroid
```
### Binary releases
See available [releases](https://github.com/orhun/systeroid/releases) that are automated by [Continuous Deployment](.github/workflows/cd.yml) workflow.
### Building from source
```sh
# clone the repository
git clone https://github.com/orhun/systeroid && cd systeroid/
# binaries will be located at:
# - target/release/systeroid
# - target/release/systeroid-tui
CARGO_TARGET_DIR=target cargo build --release
```
Also see [requirements](#requirements).
### Docker
#### Images
Docker builds are [automated](./.github/workflows/docker.yml) and images are available in the following registries:
- [Docker Hub](https://hub.docker.com/r/orhunp/systeroid)
- [GitHub Container Registry](https://github.com/orhun/systeroid/pkgs/container/systeroid)
#### Usage
The following command can be used to interactively view the documentation of selected parameters:
```sh
docker run --rm -it "orhunp/systeroid:${TAG:-latest}" --tui
```
Docker containers share the host system's kernel and its settings thus access to `/proc` and `/sys` are restricted for security. That is why it is not possible (and not recommended) to tweak the kernel parameters within a container. [\*](https://stackoverflow.com/questions/54845095/cannot-run-sysctl-command-in-dockerfile)
#### Building
Custom Docker images can be built from the [Dockerfile](./Dockerfile):
```sh
docker build -t systeroid .
```
## Usage
```
systeroid [options] [variable[=value] ...] --load[=<file>]
```
### Options
```
-a, --all display all variables (-A,-X)
-T, --tree display the variables in a tree-like format
-J, --json display the variables in JSON format
--deprecated include deprecated variables while listing
-e, --ignore ignore unknown variable errors
-N, --names print only variable names
-n, --values print only variable values
-b, --binary print only variable values without new line
-p, --load read values from file (-f)
-S, --system read values from all system directories
-r, --pattern <expr>
use a regex for matching variable names
-q, --quiet do not print variable after the value is set
-w, --write only enable writing a value to variable
-E, --explain provide a detailed explanation for variable
-D, --docs <path> set the path of the kernel documentation
-P, --no-pager do not pipe output into a pager
-v, --verbose enable verbose logging
--tui show terminal user interface
-c, --config <path> set the path of the configuration file
-h, --help display this help and exit (-d)
-V, --version output version information and exit
```
Most of the arguments/flags are inherited from `sysctl` so they have the same functionality.
### Examples
#### Listing parameters
```sh
# list all parameters
systeroid -A
# list parameters in a tree-like format
systeroid -T
# list parameters in JSON format
systeroid -J
```
To disable colors, set the [`NO_COLOR`](https://no-color.org/) environment variable.
#### Filtering by section
```sh
# only list parameters in the "kernel" section
systeroid kernel
# only list parameters in the "vm" and "user" sections
systeroid vm user
```
#### Displaying values
```sh
# print the name and value of a parameter (in "name=value" format)
systeroid kernel.hostname
# print only the value of a parameter
systeroid -n kernel.hostname
# print the name and values of the multiple parameters
systeroid kernel.hostname user.max_user_namespaces
```
#### Setting values
```sh
# set the value of a parameter
systeroid kernel.domainname="example.com"
# set the values of multiple parameters and ignore errors
systeroid -e kernel.dmesg_restrict=0 vm.panic_on_oom=1 unknown_param="test"
# set the values of multiple parameters and enforce the "name=value" format
systeroid -w fs.dir-notify-enable=1 net.mptcp.enabled=1 vm.oom_kill_allocating_task
```
#### Loading values from a file
Parameter values can be set from an [INI file](https://en.wikipedia.org/wiki/INI_file).
`sysctl.conf`:
```ini
# Use kernel.sysrq = 1 to allow all keys.
# See https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html for a list
# of values and keys.
kernel.sysrq = 16
# Append the PID to the core filename
kernel.core_uses_pid = 1
; Enable hard and soft link protection
; (If a line begins with a single '-', any attempts to set the value that fail will be ignored.)
-fs.protected_hardlinks = 1
fs.protected_symlinks = 1
```
To load it:
```sh
systeroid --load sysctl.conf
```
If no file is given, values are loaded from `/etc/sysctl.conf` as default:
```sh
systeroid --load
```
Specifying "-" as file name means reading data from standard input:
```sh
systeroid --load -
```
#### Loading values from the system directories
The list of default system directories are the following:
- `/etc/sysctl.d`
- `/run/sysctl.d`
- `/usr/local/lib/sysctl.d`
- `/usr/lib/sysctl.d`
- `/lib/sysctl.d`
- `/etc/sysctl.conf`
Use `--system` flag to load the files with ".conf" extension in these directories:
```sh
systeroid --system
```
#### Searching parameters
```sh
# search parameters using regex patterns
systeroid -r 'net.ipv4.conf.(eth|wlan)0.arp'
systeroid -r '^net.ipv6'
```
Example output of combining search with listing:
```sh
$ systeroid --names --pattern 'kernel.*_max$' --tree
kernel
├── ngroups_max
├── pid_max
└── sched_util_clamp_max
```
#### Showing information about parameters
**systeroid** can dump the parameter information from the kernel documentation. This is useful if you don't know what a parameter is used for.
```sh
# show information about a parameter
systeroid --explain oom_dump_tasks
```
Kernel documentation should be present in one of the following paths for parsing upon first launch:
- `/usr/share/doc/linux`
- `/usr/share/doc/linux-doc`
- `/usr/share/doc/linux-docs`
- `/usr/share/doc/kernel-doc-*/Documentation`
Then the parsed data is cached in `$HOME/.cache/systeroid-core` and used from there as long as the documentation is not updated. The caching mechanism can be disabled via setting the `NO_CACHE` environment variable.
This is a design choice due to the fact that different versions of kernels might be installed on different systems so the documentation might be too new or old if **systeroid** was to be shipped with a fixed set of parameter descriptions bundled in. With the parsing approach, documentation is always kept up-to-date.
However, this means you need to:
- either install the kernel documentation package (based on your distribution)
- on Arch Linux: `pacman -S linux-docs`
- on Debian/Ubuntu: `apt-get install linux-doc`
- on Fedora: `dnf install kernel-doc`
- or explicitly specify the path of the [kernel documentation](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide).
```sh
# specify the kernel documentation path explicitly
# (not needed if you have the kernel documentation installed as a package)
systeroid -E user.max_user_namespaces --docs /usr/share/doc/linux
```
To change the default pager (`less(1)`), you can use the `PAGER` environment variable. Also, you can simply use `--no-pager` flag to disable it.
```sh
systeroid -E kernel.ctrl-alt-del --no-pager
```
It is also possible to retrieve information about multiple parameters:
```sh
systeroid -E --pattern '.*ipv4.*' --no-pager
```
## TUI
### Usage
```
systeroid-tui [options]
```
```
-t, --tick-rate <ms>
set the tick rate of the terminal [default: 250]
-D, --docs <path> set the path of the kernel documentation
--save-path <path>
set the path for saving the changed parameters
-s, --section <section>
set the section to filter
-q, --query <query> set the query to search
--bg-color <color>
set the background color [default: black]
--fg-color <color>
set the foreground color [default: white]
-n, --no-docs do not show the kernel documentation
--deprecated include deprecated variables while listing
-c, --config <path> set the path of the configuration file
-h, --help display this help and exit
-V, --version output version information and exit
```
### Key Bindings
| Key | Action |
| ---------------------------------------------------------- | ---------------------------- |
| <kbd>?</kbd>, <kbd>f1</kbd> | show help |
| <kbd>up/down</kbd>, <kbd>k/j</kbd>, <kbd>pgup/pgdown</kbd> | scroll list |
| <kbd>t/b</kbd> | scroll to top/bottom |
| <kbd>left/right</kbd>, <kbd>h/l</kbd> | scroll documentation |
| <kbd>tab</kbd>, <kbd>`</kbd> | next/previous section |
| <kbd>:</kbd> | command |
| <kbd>/</kbd> | search |
| <kbd>enter</kbd> | select / set parameter value |
| <kbd>s</kbd> | save parameter value |
| <kbd>c</kbd> | copy to clipboard |
| <kbd>r</kbd>, <kbd>f5</kbd> | refresh |
| <kbd>esc</kbd> | cancel / exit |
| <kbd>q</kbd>, <kbd>ctrl-c/ctrl-d</kbd> | exit |
### Examples
#### Launching
Simply run `systeroid-tui` to launch the terminal user interface. Alternatively, you can use `systeroid --tui` command (which runs `systeroid-tui` under the hood if it is found in [`PATH`](<https://en.wikipedia.org/wiki/PATH_(variable)>)).
#### Showing help
Help menu and key bindings can be shown via pressing <kbd>?</kbd>:
#### Scrolling
Use <kbd>up/down</kbd> keys to scroll the parameter list. Alternatively, use <kbd>t/b</kbd> to scroll to the top/bottom.
Use <kbd>left/right</kbd> to scroll the parameter documentation.
#### Toggling the kernel section
Press <kbd>tab</kbd> or <kbd>`</kbd> to toggle the kernel section for filtering entries in the parameter list.
Order of the sections is `all`-`abi`-`fs`-`kernel`-`net`-`sunrpc`-`user`-`vm`.
`--section` argument can be used to start **systeroid-tui** with the specified section for filtering.
```sh
systeroid-tui --section kernel
```
#### Searching
Press <kbd>/</kbd> and type in your query to search for parameters.
Alternatively, you can start **systeroid-tui** with a pre-defined search query by using `--query` argument.
```sh
systeroid-tui --query "fs.quota"
```
#### Setting values
Press <kbd>enter</kbd> to select a parameter and set its value via command prompt.
You can press <kbd>r</kbd> to refresh the values in the parameter list.
#### Saving values
Press <kbd>s</kbd> to set a parameter value via command prompt and save its value to a file specified via `--save-path`.
Default save path is `/etc/sysctl.conf` and the values can be loaded via `systeroid --load`.
```sh
$ systeroid-tui --save-path /etc/sysctl.d/custom.conf
$ systeroid --system
```
#### Running commands
Press <kbd>:</kbd> to open the command prompt for running a command. Available commands are:
| Command | Description |
| ------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| `:help` | Show help |
| `:search` | Enable search |
| `:select` | Select the current parameter in the list |
| `:set <name> <value>` | Set parameter value |
| `:save <name> <value>` | Save parameter value to file |
| `:scroll [area] [direction] <amount>` | Scroll the list or text<br>- areas: `list`, `docs`, `section`<br>- directions: `up`, `down`, `top`, `bottom`, `right`, `left` |
| `:copy` | Copy to clipboard |
| `:refresh` | Refresh values |
| `:quit`, `:q` | Quit |
#### Copying to clipboard
Press <kbd>c</kbd> to show the options menu for copying the name, value, or documentation of the selected parameter.
\* **systeroid-tui** should be built with `clipboard` feature for enabling the clipboard support.
#### Changing the colors
Use `--bg-color` and `--fg-color` arguments to customize the colors of the terminal user interface.
```sh
# use a color name for setting the foreground color
systeroid-tui --fg-color blue
# use hexadecimal values for setting foreground/background colors
systeroid-tui --bg-color ffff99 --fg-color 003366
```
#### Viewing the parameter documentation
To view the documentation as parameters are being selected on the list, kernel documentation should be parsed as explained in the "[Showing information about parameters](#showing-information-about-parameters)" section. A specific path for kernel documentation can be given via `--docs` argument or `KERNEL_DOCS` environment variable if it is not found in one of the locations that are checked as default.
To disable this feature altogether, use `--no-docs` flag.
#### Setting the refresh rate
It is possible to specify a value in milliseconds via `--tick-rate` argument for tweaking the refresh rate of the terminal which might be necessary in some cases where better performance is desired.
```sh
systeroid-tui --tick-rate 500
```
## Configuration
**systeroid** can be configured with a configuration file that uses the [INI format](https://en.wikipedia.org/wiki/INI_file). It can be specified via `--config` or `SYSTEROID_CONFIG` environment variable. It can also be placed in one of the following global locations:
- `$HOME/.config/systeroid/systeroid.conf`
- `$HOME/.systeroid/systeroid.conf`
```sh
# set the config path via argument
systeroid --config config/systeroid.conf
# set the config path via env
SYSTEROID_CONFIG=config/systeroid.conf systeroid
# use a global path
mkdir -p "$HOME/.config/systeroid"
cp config/systeroid.conf "$HOME/.config/systeroid"
systeroid
```
See the example [systeroid.conf](./config/systeroid.conf) for the configuration options.
## Resources
### References
- [sysctl - source code](https://gitlab.com/procps-ng/procps/-/blob/newlib/sysctl.c)
- [sysctl - Wikipedia](https://en.wikipedia.org/wiki/Sysctl)
- [sysctl - ArchWiki](https://wiki.archlinux.org/title/Sysctl)
### Logo
**systeroid** logo was originally painted by [Ryan Tippery](https://ryantippery.com) as a part of the [Compositions](https://ryantippery.com/art/compositions) art collection and it is put together by me using the [Filled Spots](https://www.fontspace.com/filled-spots-font-f30755) font. Shout out to Ryan for letting me use his painting for the logo! **<3** Kudos!
### Social Links
- [](https://twitter.com/systeroid)
- [](https://orhun.dev)
- [](https://github.com/orhun)
- [](https://twitter.com/orhunp_)
### In The Media
- [Systeroid: Best Way To Set Linux Kernel Parameters (YouTube / Brodie Robertson)](https://www.youtube.com/watch?v=v3q707TRIIs)
### Funding
If you find **systeroid** and/or other projects on my [GitHub profile](https://github.com/orhun/) useful, consider supporting me on [GitHub Sponsors](https://github.com/sponsors/orhun) or [becoming a patron](https://www.patreon.com/join/orhunp)!
[](https://patreon.com/join/orhunp)
[](https://patreon.com/join/orhunp)
## Contributing
See our [Contribution Guide](./CONTRIBUTING.md) and please follow the [Code of Conduct](./CODE_OF_CONDUCT.md) in all your interactions with the project.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache 2.0 License, shall be dual licensed as above, without any additional terms or conditions.
## License
Licensed under either of [Apache License Version 2.0](http://www.apache.org/licenses/LICENSE-2.0) or [The MIT License](http://opensource.org/licenses/MIT) at your option.
## Copyright
Copyright © 2022-2023, [Orhun Parmaksız](mailto:orhunparmaksiz@gmail.com)