5 added 8 characters in body
source | link

Bash, 77 6 bytes

haltinit -p0

Assuming that the program is run as root.

Bash, 7 bytes

halt -p

Assuming that the program is run as root.

Bash, 7 6 bytes

init 0

Assuming that the program is run as root.

4 edited body
source | link

Bash, 47 bytes

halt -p

Assuming that the program is run as root.

Bash, 4 bytes

halt -p

Assuming that the program is run as root.

Bash, 7 bytes

halt -p

Assuming that the program is run as root.

3 added 33 characters in body
source | link

Bash, 4 bytes

halt -p

Assuming that the program is run as root.

halt terminates all processes and shuts down the CPU. If it is required, that this also shut down the physical machine, then it is instead 7 bytes

halt -p

Bash, 4 bytes

halt

Assuming that the program is run as root.

halt terminates all processes and shuts down the CPU. If it is required, that this also shut down the physical machine, then it is instead 7 bytes

halt -p

Bash, 4 bytes

halt -p

Assuming that the program is run as root.

2 added 33 characters in body
source | link
1
source | link