BASH without bc :: if [ echo `awk 'BEGIN{print 0.001>0.9}'` -eq 0 ]; then DO SOMETHING; fi

Question

Please help. How can accomplish this

if [ echo `awk 'BEGIN{print 0.001>0.9}'` -eq 0 ]; then DO SOMETHING; fi

But that is wrong.
What I'm trying to do is: if the first number(0.001) if greater than 0.9 then DO SOMETHING. else DO NOTHING
The numbers will always be float like 0.001, 0.03, 0.89 etc...
Ah and I MUST NOT use the bc command.

What is the source of the first number? Clearly, 0.001 is never greater than 0.9, so you must have some variable you intend to compare to 0.9. — chepner, Nov 22 '13 at 19:45

score 5 · Answer 1 · answered Nov 22 '13 at 19:49

5

To generalize it:

function gt {
    awk -v n1=$1 -v n2=$2 'BEGIN {exit !(n1 > n2)}'
}

if gt 0.01 0.9; then
    do_something
fi

answered Nov 22 '13 at 19:49

glenn jackman

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score 2 · Answer 2 · answered Nov 22 '13 at 19:46

2

This should work:

[[ $(awk 'BEGIN{print (0.001>0.9)}') -eq 0 ]] && DO SOMETHING

Or if you want to pass variables to awk:

[[ $(awk -v a='0.001' -v b='0.9' 'BEGIN{print (a>b)}') -eq 0 ]] && echo "a is smaller"

answered Nov 22 '13 at 19:46

anubhava

761,203
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569
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score 1 · Answer 3 · answered Nov 22 '13 at 19:59

Taking your existing code, and it's lack of variables, literally, then this should suffice:

DO SOMETHING

Since 0.001 is never greater than 0.9, awk should print 0, which of course is equal to 0, and so the whole test is a little pointless without using any variables...

score 1 · Answer 4 · answered Nov 22 '13 at 20:31

$ cat ./tst.sh
function cmp {
    awk -v v1="$1" -v v2="$2" 'BEGIN{
        if      (v1 > v2) { diff =  1 }
        else if (v1 < v2) { diff = -1 }
        else              { diff =  0 }
        print diff
    }'
}

if [ $(cmp "$1" "$2") -eq  1 ]; then rslt="is greater than"; fi
if [ $(cmp "$1" "$2") -eq -1 ]; then rslt="is less than";    fi
if [ $(cmp "$1" "$2") -eq  0 ]; then rslt="is equal to";     fi

printf "%s %s %s\n" "$1" "$rslt" "$2"

$ ./tst.sh 0.001 0.9
0.001 is less than 0.9

$ ./tst.sh 0.9 0.001    
0.9 is greater than 0.001

$ ./tst.sh 0.9 0.9000
0.9 is equal to 0.9000

BASH without bc :: if [ echo `awk 'BEGIN{print 0.001>0.9}'` -eq 0 ]; then DO SOMETHING; fi

4 Answers4