the.com/pid1
The first process Linux boots; everything else is its adopted children.
means Process ID 1, the initial user-space program launched by the kernel on Unix-like systems—the ancestor of all other processes, responsible for spawning and managing the init system.
from From Unix's earliest days (1970s). The kernel itself is process 0 (swapper); PID 1 is where userland begins. Originally /etc/init, now typically systemd, OpenRC, or runit depending on the distribution—a philosophical battleground for decades.
Unkillable by designSending SIGKILL to PID 1 is ignored; the system can't orphan itself.
Systemd dominanceMost major Linux distros now run systemd as PID 1, replacing traditional init scripts.
Zombie reaperAdopts orphaned processes (whose parents died) so they don't linger as zombies.
Boot to loginSpawns everything from network daemons to the login prompt you eventually see.