LDP/LDP/guide/docbook/abs-guide/factr.sh

#!/bin/bash
# factr.sh: Factor a number

MIN=2       # Will not work for number smaller than this.
E_NOARGS=85
E_TOOSMALL=86

if [ -z $1 ]
then
  echo "Usage: $0 number"
  exit $E_NOARGS
fi

if [ "$1" -lt "$MIN" ]
then
  echo "Number to factor must be $MIN or greater."
  exit $E_TOOSMALL
fi  

# Exercise: Add type checking (to reject non-integer arg).

echo "Factors of $1:"
# -------------------------------------------------------
echo  "$1[p]s2[lip/dli%0=1dvsr]s12sid2%0=13sidvsr[dli%0=\
1lrli2+dsi!>.]ds.xd1<2" | dc
# -------------------------------------------------------
#  Above code written by Michel Charpentier <charpov@cs.unh.edu>
#  (as a one-liner, here broken into two lines for display purposes).
#  Used in ABS Guide with permission (thanks!).

 exit

 # $ sh factr.sh 270138
 # 2
 # 3
 # 11
 # 4093