$# shows the count of the arguments passed to the script.
du -s /home/user1 ….where user1 is the user for whom the total disk space needs to be found.
csh,ksh,bash,Bourne . The most commonly used and advanced shell used today is “Bash” .
#!/bin/sh a=1 b=1 echo $a echo $b for I in 1 2 3 4 5 6 7 8 do c=a b=$a b=$(($a+$c)) echo $b done