要实现一个命令-谁

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 " ###

Makefile
who1.c