/proc/sysrq-trigger - SysRq function

/proc/sysrq-trigger (since Linux 2.4.21) Writing a character to this file triggers the same SysRq function as typing ALT-SysRq-<character> (see the description of /proc/sys/kernel/sysrq). This file is normally writable only by root. For further details see the Linux kernel source file Documentation/admin-guide/sysrq.rst (or Documentation/sysrq.txt before Linux 4.10).

/proc/sysrq-trigger - SysRq function

proc(5) Linux man-pages 6.9.1 2024-05-02 proc_sysrq-trigger(5)