Shell Programming and Scripting

function setFieldsByWidth(   i,n,FWS,start,copyd0) {
  # Licensed under GPL Peter S Tillier, 2003
  # NB corrupts $0
  copyd0 = $0                             # make copy of $0 to work on

  n = split(FIELDWIDTHS,FWS)

  if (n == 1) {
    print "Warning: FIELDWIDTHS contains only one field width." > "/dev/stderr"
    print "Attempting to continue." > "/dev/stderr"
  }

  start = 1
  for (i=1; i <= n; i++) {
    $i = substr(copyd0,start,FWS[i])
    start = start + FWS[i]
  }
}

#Note that the "/dev/stderr" entries in some lines have wrapped.

#I then call setFieldsByWidth() in my main awk code as follows:

BEGIN {
  #FIELDWIDTHS="1 3 8 8 5 9 1 9" # for example
  OFS=" "
}
FNR==NR {
  FIELDWIDTHS=(FIELDWIDTHS)?FIELDWIDTHS FS $0: $0
  next
}
!/^[  ]*$/ {
  saveDollarZero = $0 # if you want it later
  setFieldsByWidth()
  # now we can manipulate $0, NF and $1 .. $NF as we wish
  print $0 OFS
  next
}

#!/bin/ksh

typeset SEP=','
typeset in=input.dat
typeset out=output.dat
typeset lay=layout.dat

typeset compare
typeset replace
typeset i=1

## Parse the layout and build perl regex strings
cat $lay | while read size
do
  compare="$compare(.{$size})"
  replace="$replace\${$i}${SEP}"
  i=$((i+1))
done

cat $in | perl -pe "s/$compare/${replace%,}/g" > $out

awk '
NR==FNR{a[++c]=$0; next}
{ j=1
  for(i=1;i<=c;i++) {
    printf("%s ",substr($0,j,a[i]))
    j+=a[i]
  }
  print ""
}' text1.txt $fixedwidthfile

$
$
$ cat layout.dat
2
4
6
3
$
$ cat input.dat
AABBBBCCCCCC
DDDEEFFFFGGGGGG
HHHIIJJJJKKKKKKLLL
$
$
$ ##
$ perl -ne 'chomp;
          if ($ARGV eq "layout.dat") {
            $n += $_;
            $pattern .= "A$_ ";
            $format .= "%s ";
          } else {
            $x .= $_;
            do {$x=~/^(.{$n})(.*)$/ and $y=$1 and $x=$2;
                printf("$format\n", unpack($pattern, $y));
            } until (length($x) < $n)
          }' layout.dat input.dat
 
AA BBBB CCCCCC DDD
EE FFFF GGGGGG HHH
II JJJJ KKKKKK LLL
$
$