awk function syntax error?

Question

Can someone see why I get

awk: cmd. line:8:   function mma(num) {
awk: cmd. line:8:   ^ syntax error
awk: cmd. line:8:   function mma(num) {
awk: cmd. line:8:                     ^ syntax error

from this script?

echo "0.24 0.21 0.22 1/1282 10953" | awk '{

  min=""
  max=""
  avg=""

  # find min, max, avg
  function mma(num) {
    if(min==""){min=max=$1};
    if($1>max) {max=$1};
    if($1<min) {min=$1};
    total+=$1;
    count+=1;
    avg=total/count;
  }

  mma($1)
  mma($2)
  mma($3)

  print avg, max, min
}'

There are few points to be noted here eg--> while loop doesn't have done in it to complete it's syntax. — RavinderSingh13
– RavinderSingh13, Commented May 25, 2018 at 11:49
Your function cannot be defined in an action from a (pattern){ action } rule of your awk script. — kvantour
– kvantour, Commented May 25, 2018 at 11:50
If you could show us sample input and sample output in CODE TAGS in your post we could try to help you more here. — RavinderSingh13
– RavinderSingh13, Commented May 25, 2018 at 11:55
@SandraSchlichting, kindly post the expected output too in your post. — RavinderSingh13
– RavinderSingh13, Commented May 25, 2018 at 11:57

Community · Accepted Answer · 2020-06-20 09:12:55Z

5

Definitions of functions can appear anywhere between the rules of an awk program. From the POSIX standard :

The awk language also provides user-defined functions. Such functions can be defined as:
function name([parameter, ...]) { statements }
A function can be referred to anywhere in an awk program; in particular, its use can precede its definition. The scope of a function is global. <snip> Function definitions can appear anywhere in the program where a pattern-action pair is allowed.

This means a valid awk program looks like :

( pattern1 ) { action1 }
function name([parameter, ...]) { statements }
( pattern2 ) { action2 }
...

In your original code, you wrote the incorrect

( pattern ) { function name([paramter, ...]) { statements }
             action }

So the corrected version of your awk part would be:

awk 'function mma(num) {
        if(min==""){min=max=$1};
        if($1>max) {max=$1};
        if($1<min) {min=$1};
        total+=$1;
        count+=1;
        avg=total/count;
     }
     { min=""; max=""; avg=""
       mma($1); mma($2); mma($3)
       print avg, max, min
     }'

update: from the comments, it might be more useful to use

awk '{ avg=($1+$2+$3)/3; min=avg; max=avg;
       min=($1<min) ? $1 : min; max=($1>max) ? $1 : max
       min=($2<min) ? $2 : min; max=($2>max) ? $2 : max
       min=($3<min) ? $3 : min; max=($3>max) ? $3 : max
       print avg,max, min } ' /proc/loadavg

However, this is questionable as taking the average of averages is very ...

Also interesting might be the sar command.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered May 25, 2018 at 12:03

kvantour

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11 Comments

kvantour Over a year ago

@SandraSchlichting this works without errors on my side, I am however a bit puzzled what the code does or its intentions should be. As your function argument num is never used. By default, this will always return the first element of /proc/cpuinfo

Sandra Schlichting Over a year ago

Ok, so that might be the problem then. I though the arguments for a function could be anything. I just called it num and thought it would be $1 inside the function definition. But that is not the case?

Sandra Schlichting Over a year ago

So I guess all $1 in the function should be num?

kvantour Over a year ago

$i always refers to field number i.

kvantour Over a year ago

@SandraSchlichting could you please explain your intentions for this script. Since /proc/loadavg shows the average load for the first 1,5 and 10 minutes of the system. Do you want to find the min/max/avg of these 3 numbers? Or do you want to have the min/max/avg per field of the continuously updated /proc/loadavg. If the latter, then this script will not work as intended.

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