UNIX for Dummies Questions & Answers

Hello, I have a quick question that is not related to homework in any way shape or form (in case anyone wanted to know). My question is thus:

I have a file "temp" that has the two values say "5" and "3" (separated by a white space). Now, I want to simply write an if-else statement that reads file temp, and if $1 (5) is less than $2 (3) it prints OK, else NO. The values for $1 and $2 do change. My attempt is:

Code:

if [[ ($1 -lt $2) temp]]; 
    then echo "OK"
else 
    echo "NO"
fi;

Right now I'm getting a syntax error. Help would be very much appreciated. Thanks in advance.

Code:

read a b < temp
if [ "${a}" -le "${b}" ]; then
   echo OK
else
   echo NO
fi

Thanks for the quick reply!
Very helpful. Quick follow-up question. I don't know if this matters, but my values are not necessarily integers, and I got this warning:

Code:

line 21: [: 5.039814: integer expression expected

I don't know if there is an easy way to deal with this and/or if this is an actual problem or not?

Moderator's Comments:

Please use code tags when posting data and code samples!

If your shell doesn't support floating point math (not too many do), try this:

Code:

#!/bin/ksh

read a b < temp
if [ "$(echo "if (${a} < ${b}) 1" | bc)" -eq 1 ] ; then
   echo OK
else
   echo NO
fi

I'm not sure what the above expression does, but it did work for the case when a < b, however when a > b I get:

line 29: [: : integer expression expected

always some issue isn't there

could you post the entire script? What's on line 29?
This test script works just fine:

Code:

#!/bin/ksh

a=1.72
b=1.73

if [ "$(echo "if (${a} > ${b}) 1" | bc)" -eq 1 ] ; then
   echo ">"
else
   echo "<"
fi;

On line 29 I have:

read a b < temp_star1

I have a lot of comments before that, and a few simple shell commands that should not affect anything. I just noticed I am using

#!/bin/bash

perhaps that's the problem? I'll check. Thanks.