Link, Alias and Environment

Alias
[root]# alias
[root]# alias ls='ls -l'
[root]# unalias ls

[root]# alias le='ls -ltr'
[root]# alias ping='ping -c4'

Links
[root]# ln -s /usr/jakarta-ant-1.6 /usr/local/ant
[root]# ln -s `pwd` newlink

Set/Unset
[root]# set RGS_HOME=/usr/local/rgs
[root]# export RGS_HOME
[root]# unset -v RGS_HOME

Environment
[root]# env
[root]# dmesg --> view the booting process log
[root]# which

CPU information
[root]# uname -r
[root]# cat /proc/cpuinfo
[root]# grep 'physical id' /proc/cpuinfo | sort | uniq | wc -l --> check number of CPUs
[root]# grep ^processor /proc/cpuinfo | wc -l --> check how many virtual processors

Memory information
[root]# cat /proc/meminfo