I am new to bash scripting. My code is :
MK=M
SM=1.4
if [[ $MK == "M" ]]
then
if [ $SM -gt 1.3 ]
then
echo "Greater than 1.3M"
else
echo "Less than 1.3M"
fi
else
echo "Not yet M...."
fi
Reply:
/tmp/tmp.sh: line 6: [: 1.4: integer expression expected
Less than 1.3M
What am i doing wrong ?
It's ultimately because bash is not terribly patient when it comes to floating point numbers. In very simple terms here, I would suggest you do one of two things:
It looks like you are trying to determine if something is larger than 1.3 Mb or not, is this correct? If this is the case, then leave everything the way you have it, and just use Kb for $sm and the compare
like this:
#/bin/bash
mk="p"
km="p"
sm="1400"
ms="1300"
if [[ $mk == $km ]]
then
if [ $sm > $ms ]
then
echo "Greater than 1.3M"
else
echo "Less than 1.3M"
fi
else
echo "Not yet M...."
fi
or
Use bc for the calculation of the floating point numbers...
# /bin/bash
mk="p"
km="p"
sm="1.4"
ms="1.3"
if [ $(echo "$mk == $km" | bc) ]
then
if [ $(echo "$sm > $ms" | bc) ]
then
echo "Greater than 1.3M"
else
echo "Less than 1.3M"
fi
else
echo "Not yet M...."
fi
One more thing to note here, is that, as you can see from my code, I have primed new variables with the data, rather than using raw letters and numbers in boolean and compare operations, which can have some genuinely unexpected results. Also, while they may work in some conditions, temporarily, bash prefers all variable names to be in lower-case. Let me know if you have any questions.. However, I have tested both code chunks, and they both work fine.
bc). > in the context of [ ... ] and [[ ... ]] performs lexical comparison, not numerical. Bash does not care about the case of variables, but it's preferable to stay away from all-uppercase variables to avoid clashes with environment variables and Bash's built-in variables.Here's what man bash says:
arg1 OP arg2... Arg1 and arg2 may be positive or negative integers.
You seem to be trying to compare floating point numbers.
