# phpman > man > ON_AC_POWER(1) > **TLDR:** A simple utility which tests if a computer is running on line power. > - Test if a computer is running on line power: `on_ac_power` *Source: tldr-pages* --- [ON_AC_POWER(1)](https://www.chedong.com/phpMan.php/man/ONACPOWER/1/markdown) General Commands Manual [ON_AC_POWER(1)](https://www.chedong.com/phpMan.php/man/ONACPOWER/1/markdown) ## NAME on_ac_power - test whether computer is running on AC power ## SYNOPSIS **on**___**ac**___**power** ## DESCRIPTION **on**___**ac**___**power** checks whether the system is running on abundant power (such as AC mains, an USB charger, etc), as opposed to battery power. ## OPTIONS None. ## EXIT STATUS ### 0 (true) ### 1 (false) ### 255 (false) ## CAVEATS The vast majority of desktops and servers have no power sensors, thus they return 255 "un‐ known"; for most purposes you'd want to consider this answer to imply mains power — note that 255 evaluates as false for the shell. This program currently provides only information known to the kernel; it doesn't (yet?) query userspace daemons such as nut which may provide further information. ## AUTHOR This manual page was written by Steve Dodd <>, was updated by Thomas Hood then by Adam Borowski. 12 March 2018 [ON_AC_POWER(1)](https://www.chedong.com/phpMan.php/man/ONACPOWER/1/markdown)