how to assign options to scripts ?

okay, i have to write a program that gets two numbers from the user, and prints the numbers in between both numbers out, including the two numbers. that should not be the hard part, i can just assign a while loop to end on the higher variable.

the hard part is that the script is supposed to have two possible options. : -e and -o

if i typed :
$ script1 -o 4 9

it would print out all the odd numbers between 4 and 9.

my question is, how do i assign and define an arbitrary option ?

-ivalice

http://www.tldp.org/LDP/abs/html/internal.html#EX33

pan about a page up and read the section on getopts

-Steven

Thank you, that page has been a great help.

Another problem I am stuck with, however.
When I "grab" the input from the user, the integers should be stored in $1 and $2. I am trying to write an 'if' statement to compare which integer is larger, so I may proceed with the program. (If one is larger, then incrementing certain variables is in order)

But I get a 'Non-numeric error', when I write:

if [ "$1" -gt "$2" ];
then
#some code in here
fi

I changed the $2 in the 'if' statement to 0, and it runs without the error.

My question is how can I compare two integers that are in $1 and $2 to see which is larger?

-ivalice

edit: btw, the tried string conditions as well, such as ">" and "<" and it still does not work.

you are comparing strings
if [ "$1" -gt "$2" ];
and if the user enter less then two strings, you get another error
try something like:
[ $# -le 1 ] && exit 1
here is a numerical comp, so check if it's numerical
case $1 in [0-9]*[0-9]) ;; exit 1;; esac
case $2 in [0-9]*[0-9]) ;; exit 1;; esac
if [ $1 -gt $2 ]
then ....
fi
see man pages 'sh, csh, ksh, test, ...'
i would use an other tool to do this
---- nota
if [ "$1" -gt "$2" ][color red];[/color]
then
#some code in here
fi
and
if [ "$1" -gt "$2" ] ; then
#some code in here
fi
are not the same

actually they are supposed to compare integers, not strings, but i think i get what you are saying. however, i make sure to enter exactly two integers, for example:

$ ./prog4 5 8
so it should be $1=5 and $2=8


yes, this is good for error checking. thank you. i will try and incorporate it into the program.



this is also good error checking, in case the user inputs a letter.

i still need a solution to compare those two numbers however. i think the last bit of code you wrote in your reply, was just to tell me that there is a difference in having a space after the "]" in this statement : "if [ "$1" -gt "$2" ] ; "

i didn't leave a space there. so that should not be a problem.


more help = much thanks !
-ivalice