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Old 03-03-2014, 06:00 AM   #1
massy
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How to compare a decimal variable with a number?


tempr in my code is a decimal number like 23.8!
I want to check if it is less than -20 or great than 50 or not! my
Code:
if [ "$hour" != "$ch" ] || [ "$min" -lt $((cm-10)) ] || [ "$min" -gt $(($cm+10)) ] || [ $(echo "$tempr < -20" | bc -l ) ] || [ $(echo "$tmepr > 50" | bc -l ) ]
        then
 
Old 03-03-2014, 06:18 AM   #2
NevemTeve
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Try it in little steps:

step #1:
Code:
NUM=3.212; INT=${NUM%.*}; echo $INT
if [ $INT -lt 4  -a $INT -ge 2 ]; then
    echo "so far so good"
fi;
 
1 members found this post helpful.
Old 03-03-2014, 06:43 AM   #3
Ramurd
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The problem is the if statement with a lot of reverse logic in it; if one of the statements evaluates to 'true', it will stop evaluating the rest of the statements; Question could also be: which statement to evaluate.

Code:
if [ "$hour" != "$ch" ] 
then
...
fi
So, if $hour equals $ch, the next test has to be evaluated, otherwise it is already true and doesn't become more or less true; So be careful linking all those tests together.

Then again, for the original question posted, bc has a good thing for you:

Code:
cur_temp="20.5"
tst_temp="20"
if [ $(echo "$cur_temp > $tst_temp" | bc -l) ]
then
     echo "It's more than 20."
else
     echo "It's less than 20."
fi
 
  


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