How do I determine whether a particular running Ubuntu system was booted using EFI/UEFI, or BIOS?
3 Answers
The easiest way is to check to see if /sys/firmware/efi
exists. It does not appear if you booted using traditional BIOS.
#!/bin/bash
[ -d /sys/firmware/efi ] && echo UEFI || echo BIOS
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Tested on QEMU 2.0.0, OVFM and Ubuntu 14.04: github.com/cirosantilli/runlinux/tree/… Sep 7, 2015 at 13:36
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5nitpick, that expression is POSIX so should work in a variety of shells, not just
bash
– iruvarNov 30, 2019 at 19:45 -
Deprecated
The answer below is a method that may not always work.
Instead use Colin's answer based on/sys/firmware/efi
.
It's very easy to tell if a system was booted in EFI (or not, in which case it must be BIOS):
Just use dmesg | grep "EFI v"
This will return a line like this, if the system was booted off of EFI:
[ 0.000000] EFI v2.00 by American Megatrends
Or return nothing if it was not, in which case it was booted off of BIOS
Example of bash script usage based on grep's exit code:
... dmesg | grep -q "EFI v" # -q tell grep to output nothing if [ $? -eq 0 ] # check exit code; if 0 EFI, else BIOS then echo "You are using EFI boot." else echo "You are using BIOS boot" fi ...
Source: For how to determine if an EFI system is using legacy-BIOS emulation or not, as well as more information on testing for EFI and EFI compatibility, along with the strings for a number of EFI vendors/versions, please see this page from the Ubuntu Developer Summit for Precise.
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2I'd simplify that to
if dmesg | grep -Fq "EFI v"; then ...
. No point in running the[
command in addition, just to test for success/failure.$?
is mainly useful for checking for specific errors.– geirhaJul 12, 2012 at 10:50 -
3This is brittle, as there is no guarantee that the string searched for is generated by the desired feature. Jul 13, 2012 at 1:28
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2@izx, any script can happen to write "EFI v" as part of something else. If that happens on a BIOS machine, this would be a false positive. Jul 13, 2012 at 1:37
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2Best not to grep for text in the kernel log, it is subject to change. Best to look at /sys/firmware/efi Jul 27, 2012 at 18:24
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2I'd like to mention however that this is a great way to get the EFI version! Sep 3, 2012 at 2:01
Python code to check if system is booted with UEFI or ROM BIOS:
import os,sys def main(): if(os.path.exists("/sys/firmware/efi")): print"\n\n System is booted with uefi!" else: print"\n\n System is booted with rom bios" main() sys.exit(0)