2

I have a basic script to find the max of 2 numbers using a user-defined function; but, I need to convert it to accept 4 numbers, and I am having a hard time. Here is the script.

#!/bin/bash
echo $1 $2 | awk '
{
    print max($1, $2)
}

function max(a, b) {
    return a > b ? a: b
}'

You would simply execute it by doing: ./scriptname 1 2 (or whatever two numbers you want) and the output would be the max of the two numbers. I think I can just do the following.

#!/bin/bash
echo $1 $2 $3 $4 | awk '
{
    print max($1, $2, $3, $4)
}

function max(a, b, c, d) {
    return a < b ? a: b
}'

I am having trouble with line 7, the "return" line. Any suggestions?
Thanks -CableGuy

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6
  • And? Edit it, and look at the preview before submitting. Commented Mar 19, 2018 at 17:37
  • Just a heads-up; your title says "finding max of 4 numbers", your initial function says & computes the max, but then your final script/function both say & compute the minimum. Commented Mar 19, 2018 at 18:13
  • Yeah i see that, i just forgot to modify it from the original minimum function Commented Mar 19, 2018 at 18:17
  • I fixed the min to max Commented Mar 19, 2018 at 20:17
  • If we have max2(a,b) returning the max of inputs, and want max4(a,b,c,d) returning max of inputs. Then not that max4(a,b,c,d) = max2(max2(a,b),max2(c,d)) or equivalently max2(max2(max2(a,b),c),d) Commented Mar 19, 2018 at 20:20

4 Answers 4

Reset to default
4

If you don't mind using Bash instead of AWK:

find_max() {
  local max number

  max="$1"

  for number in "${@:2}"; do
    if ((number > max)); then
      max="$number"
    fi
  done

  printf '%d\n' "$max"
}

Usage:

$ find_max 12 64 2 455 23 99
455
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2
  • I have to use AWK unfortunately Commented Mar 19, 2018 at 17:48
  • 1
    @cableguy5533 I see. I've added an awk tag but I recommend you to state this in the question itself. I'd be glad to provide an awk-only answer if I knew it. Good luck and welcome to Unix & Linux. Commented Mar 19, 2018 at 18:01
3

You can use the 2-argument function - multiple times:

$ cat scriptname 
#!/bin/bash
echo $1 $2 $3 $4 | awk '

function min(a, b) {
    return a < b ? a: b
}

{
    print min(min(min($1,$2),$3),$4)
}'

then for example

$ ./scriptname 3 1.2 -0.4 77
-0.4

If you're required to write it as a 4-argument function, then I'd suggest something like

function min(a, b) {
    return a < b ? a : b
}

function min4(a,b,c,d) {
    return min(min(min(a,b),c),d)
}

{
    print min4($1,$2,$3,$4)
}
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0
0

You can try with this awk :

echo -3.89 -1.2 -0.217 -48 | awk '{a=$1;for(i=2;i<=NF;i++)a=$i>a?$i:a;print a}'
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0
0

The num-utils package includes numbound which solves the general problem, (it's not limited to 4 args):

printf "%s\n" 5 88.3 22 -22 -333 5 | numbound

Output:

88.3

That can be made into a simple function that parses command line arguments:

max() { printf "%s\n" "$@" | numbound ; }

Example:

max 55 33 2 99 22

Output:

99
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