$ /usr/bin/kill --help
Usage: kill [-fW] [-signal] [-s signal] pid1 [pid2 ...]
kill -l [signal] | -L
Send signals to processes
-f, --force force, using win32 interface if necessary
-l, --list print a list of signal names
-L, --table print a formatted table of signal names
-s, --signal send signal (use kill --list for a list)
-W, --winpid specified pids are windows PIDs, not Cygwin PIDs
(use with extreme caution!)
-h, --help output usage information and exit
-V, --version output version information and exit
没有手册页
所以该程序属于cygwin包。
并且没有手册页。但你可以直接询问程序帮助