system

shutdown  -h  now

shutdown  -r  now

shutdown  -h  11:23

shutdown  -h  +10

sync; sync; sync; reboot

pstree [-A|U] [-up]

-A  

-U

-p

-u 

free [-b|-k|-m|-g] [-t]

-b 

-t  

uname [-asrmpi]

uptime

vmstat [-a] 

vmstat [-fs]                     

vmstat [-S]                 

vmstat [-d]                    

vmstat [-p] 

fuser -uv /proc

cat
/proc/loadavg

/proc/cpuinfo

/proc/meminfo

getconf LONG_BIT