oBattery

A lightweight, simple C program to check and display the battery percentage of a Linux system.

Overview

oBattery reads battery information directly from Linux system files (/sys/class/power_supply/) and displays the current battery percentage. It's designed to be minimal, fast, and dependency-free.

Features

• Lightweight and minimal dependencies
• Written in pure C
• Simple and accurate battery calculation
• Linux-only (uses /sys/class/power_supply/)
• Fast execution
• Easy to integrate into shell scripts or status bars
• Highly customizable output formats

Prerequisites

• GCC compiler
• Linux system with battery support
• Standard C library (libc)

Installation

From AUR (Arch User Repository)

If you're using Arch Linux or an Arch-based distribution, you can install oBattery directly from the AUR:

Using yay:

yay -S obattery

Using paru:

paru -S obattery

Using makepkg:

git clone https://aur.archlinux.org/obattery.git
cd obattery
makepkg -si

Manual Compilation

Compile

gcc -o obattery code.c

Install (Optional)

sudo install -Dm755 obattery /usr/local/bin/obattery

Run

./obattery

Or if installed system-wide:

obattery

Usage

Simply execute the binary to display your current battery percentage:

obattery

Options

obattery [options]

Available options:

• -p, --precision <num> - Set the number of decimal places (default is 2)
• -n, --number - Return only the numeric value (no text or % symbol)
• -h, --help - Show help message
• -v, --version - Show program version
• -a, --author - Show program author

Output Examples

Default output:

obattery
# Output: Battery: 85.50%

Numeric value only (perfect for status bars):

obattery -n
# Output: 85.50

With custom precision:

obattery -p 0
# Output: Battery: 86%

Numeric with no decimals:

obattery -n -p 0
# Output: 86

How It Works

oBattery reads from the Linux power supply interface:

• /sys/class/power_supply/BAT0/energy_current - Current battery energy
• /sys/class/power_supply/BAT0/energy_full - Full battery capacity

It calculates the percentage as: (current_energy / full_energy) × 100

Integration

With i3statusbar, Polybar, or Dwmblocks

For maximum customization, use the -n flag to get only the numeric value:

obattery -n -p 0

This will output just the number (e.g., 85), allowing you to format it however you like in your status bar configuration.

Example with Polybar:

[module/battery]
type = custom/script
exec = obattery -n -p 0
interval = 5
format = <label>
format-prefix = "🔋 "
label = %output%%%

Example with i3status:

# In your status bar script
echo "BAT: $(obattery -n -p 0)%"

With Shell Scripts

BATTERY=$(obattery)
echo "$BATTERY"

Or for just the number:

BATTERY=$(obattery -n -p 0)
echo "Battery: $BATTERY%"

Troubleshooting

Battery not detected:

• Verify /sys/class/power_supply/ exists on your system
• Check if BAT0 is the correct battery device name (may vary by system)
• Run ls /sys/class/power_supply/ to see available devices

License

GNU General Public License v3.0

Permissions of this strong copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights.

Contributing

Contributions are welcome! Feel free to submit issues or pull requests.

Author

spyflow

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Made for Linux users.