busyboxのntpd を ntpdate みたいに使う方法
ntpd -q -p 192.168.0.1
# ntpd --help
BusyBox v1.35.0 () multi-call binary.
Usage: ntpd [-dnqNw] [-S PROG] [-k KEYFILE] [-p [keyno:N:]PEER]...
NTP client/server
-d[d] Verbose
-n Run in foreground
-q Quit after clock is set
-N Run at high priority
-w Do not set time (only query peers), implies -n
-S PROG Run PROG after stepping time, stratum change, and every 11 min
-k FILE Key file (ntp.keys compatible)
-p [keyno:NUM:]PEER
Obtain time from PEER (may be repeated)
Use key NUM for authentication
If -p is not given, 'server HOST' lines
from /etc/ntp.conf are used
