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Shell Programming and Scripting

Check if a variable is zero

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Top Forums Shell Programming and Scripting Check if a variable is zero
# 8  
Old 12-15-2010
Quote:
Originally Posted by BeefStu
The problem is you are testing with -eq which denotes a number.

This works in ksh.

#!/bin/ksh

func1()
{
var="574E47303030303030303030303030303030303135313937"
echo "$var"
}


ret=$(func1)
if [ "$ret" != 0 ] ## change your test to != instead of -eq
then
echo "Null"
else
echo "Not Null"
fi
return 0
I guess this is what I was looking for...Thank you!! That really helped.
# 9  
Old 12-15-2010
Lateral thought approach which works with most shells.
Treat the long number as a string (as previous posters advise) and check whether all the characters are zero by removing all zero characters.

Code:
var="000000000000000000000000000000000000000000000000"
if [ -z "`echo $var|tr -d '0'`" ]
then
        echo "NULL"
fi
#
var="574E47303030303030303030303030303030303135313937"
if [ ! -z "`echo $var|tr -d '0'`" ]
then
        echo "NOT NULL"
fi
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