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Top Forums UNIX for Dummies Questions & Answers (+ sign) Unexpected arithmetic expr script interpretation Post 302089666 by Glenn Arndt on Wednesday 20th of September 2006 09:44:43 AM
Old 09-20-2006
It's happening because when you run the lazyadd2 script, it is unaware of what you want the values of $num1 and $num2 to be. It is only going to know $1, $2, $3, etc. You can do this:

$ num1=1
$ num2=2
$ . lazyadd2

Or do it in the lazyadd2 script itself:
Code:
#!/bin/bash
num1=$1
num2=$2
num3=`expr $num1 + $num2`
echo $num3

...and run it the same way you run lazyadd1 (i.e., lazyadd2 1 2).
 

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let(1)								   User Commands							    let(1)

NAME
let - shell built-in function to evaluate one or more arithmetic expressions SYNOPSIS
ksh let arg... ksh93 let [expr...] DESCRIPTION
ksh Each arg is a separate arithmetic expression to be evaluated. ksh93 let evaluates each expr in the current shell environment as an arithmetic expression using ANSI C syntax. Variables names are shell vari- ables and they are recursively evaluated as arithmetic expressions to get numerical values. let has been made obsolete by the ((...)) syn- tax of ksh93(1) which does not require quoting of the operators to pass them as command arguments. EXIT STATUS
ksh ksh returns the following exit values: 0 The value of the last expression is non-zero. 1 The value of the last expression is zero. ksh93 ksh93 returns the following exit values: 0 The last expr evaluates to a non-zero value. >0 The last expr evaluates to 0 or an error occurred. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
ksh(1), ksh93(1), set(1), typeset(1), attributes(5) SunOS 5.11 2 Nov 2007 let(1)
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