set PATH in Linux/Unix

To set "/home/k" as PATH,

    export PATH=$PATH:/home/k

To display current PATH,  

    echo $PATH

To set permanent PATH,

(1) vim  $HOME/.profile     or    vi  .bash_profile   (in root directory (account home))

(2) add  "export PATH=$PATH:/home/k"  in the text file

(3) save 

details of  "export PATH=$PATH:/home/k" 

$PATH -  current PATH

: -  divider between PATH

It is possible to set variable as PATH.  For example,

LAMMPSHOME=/usr/global/lammps
PATH=$PATH:$LAMMPSHOME/bin