unary operator expected


 
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# 1  
Old 03-06-2009
Java unary operator expected

hi

i am trying to compare a value with value 50. but i am getting
"[: -lt: unary operator expected"

I am using

Code:
 if [ $j -lt 50 ]
then 
   echo "------------"

fi

please help

thanks in advance
Satya
# 2  
Old 03-06-2009
If $j has no value at all, the expression will be invalid because it will vanish entirely, making it look like just [ -j 50 ]. Wrap $j in double-quotes and it won't vanish, becoming [ "" -lt 50 ] , which still isn't altogether sensible -- comparing a blank string to an integer -- but at least has correct syntax.
# 3  
Old 03-06-2009
Quote:
Originally Posted by Satyak
i am trying to compare a value with value 50. but i am getting
"[: -lt: unary operator expected"

I am using

if [ $j -lt 50 ]
then
echo "------------"

fi

Make sure that $j expands to a value. Best is to set it explicitly, but you can also give it a default value (0 in this example):

Code:
if [ ${j:-0} -lt 50 ]

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