#! /usr/bin/gawk -f

# usage: 
#   get-max-field-width -v field=FNUM < INFILE

# Prints the maximum length of field FIELDNUM in all records of INFILE

function error(msg)
{
  printf "%s\n", msg > "/dev/stderr";
  abort = 1; exit 1;
}

BEGIN {
  abort=-1;
  if (field=="") 
    { error("must specify \"-v field=NUM\""); }
}

/./ { 
  if(abort >= 0) exit abort;
  m = length($(field));
  if (m > max) { max = m; }
}

END {
  if(abort >= 0) exit abort;
  printf "%d\n", max;
}