I want to run a Unix command 100 times using a for loop from 1 to 100. Can you tell me how to take a block of numbers in a loop under KSH or BASH shell?

You can use the following syntax to run a for loop.

Ksh For Loop 1 to 100 Numbers

#!/bin/ksh
# Tested with ksh version JM 93t+ 2010-03-05
for i in {1..100}
do
 # your-unix-command-here
 echo $i
done

Bash For Loop 1 to 100 Numbers

#!/bin/bash
# Tested using bash version 4.1.5
for ((i=1;i<=100;i++)); 
do 
   # your-unix-command-here
   echo $i
done

Dealing With Older KSH88 or Bash shell

The above KSH and Bash syntax will not work on older ksh version running on HP-UX or AIX. Use the following portable syntax:

#!/usr/bin/ksh
c=1
while [[ $c -le 100 ]]
do 
  # your-unix-command-here
   echo "$c"
   let c=c+1
done