资 源 简 介
To realize a linux command --who
First you should know what can comnmand --who do ? Second you should know how can command --who work?
**Third try to realize command --who
## man who ##
NAME
who - show who is logged on**
SYNOPSIS
who OPTION... FILE | ARG1 ARG2
DESCRIPTION
-a, --all
same as -b -d --login -p -r -t -T -u
If FILE is not specified, use /var/run/utmp. /var/log/wtmp as FILE is
common. If ARG1 ARG2 given, -m presumed: am i" or mom likes" are
usual.
## From this you can find file /var/run/utmp. /var/log/wtmp as FILE is ##
## common where command used ##
man -k utmp
search some file about utmp or wtmp from man help
### you can find utmp " utmp(4) -utmp and wtmp entry formats " ###
