A battery status program for x86-64 Linux laptops in the form of a 323-byte ELF executable.

Usage

$ btry
30.6 Wh / 31.1 Wh (98%)

Sometimes there are no energy_now and energy_full files, but charge_* files instead (at least on my ThinkPad X220). If this is the case, btry prints ampere hours instead of watt hours.

$ btry
2.2 Ah / 2.8 Ah (78%)

Installation

base64 -d <<EOF | unxz -Fraw --lzma2=dict=4K > btry && chmod +x btry
4AFCAQwAAD+R1tX9PhIqqLiC7tM26Rkl412GOAZaMsLDphi1cs8l0AaEDYi5pbQ4OZtD5X+bx3
SiqJd2Ay7FQOvX6bMXQizytQZKnGUfq976P5Et40R5tPw+am9xZTDtd/5iGodqK+XogOs06Zd4
mRnkOjzetIxfm/t8PusP/W0W7qdQfjmsJp01et83zL1NsDWZwaqXVgB/mizP3rDS/Yfw3sv1WS
Scke1AeMGQoQEnR7E8nDUGet9HQCLKNICtrVQ2m921mURGttfT6H+wttPkKUJRNgGQSMIVmAnH
RLFAgAmsaG/M/dbt84QXLFNCbBnFZfGukumWuKfoIsSEHIip7jL2FuBEUlC49Vr8NcnLlAAA
EOF

Limitations

• Anything that's not x86-64 and Linux is definitely not supported.
• I don't know how standard/portable the /sys/class/power_supply/BAT0 path used actually is.
• If neither an energy_full nor a charge_full file exists in /sys/class/power_supply/BAT0, an infinite loop results.
• Extra batteries (like in the ThinkPad T480) are ignored.

Build instructions

Linux on x86-64

make

Other platforms

No.

Notes

When my ThinkPad X220 is plugged in at the time I wake it from suspend mode, I get the charge_now file. When it is not plugged in I get the energy_now file. At least I think that's how it works.