systemd sd_booted 3 sd_booted Test whether the system is running the systemd init system #include <systemd/sd-daemon.h> int sd_booted void sd_booted() checks whether the system was booted up using the systemd init system. On failure, this call returns a negative errno-style error code. If the system was booted up with systemd as init system, this call returns a positive return value, zero otherwise. Internally, this function checks whether the directory /run/systemd/system/ exists. A simple check like this can also be implemented trivially in shell or any other language. systemd1, sd-daemon3