#!/usr/bin/env bash

# @(#) s4	Demonstrate FIELDWIDTH and substitution.

# Utility functions: print-as-echo, print-line-with-visual-space.
pe() { for i;do printf "%s" "$i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
# Context for local environment.
[ -f ~/bin/context ] && . ~/bin/context awk

FILE=${1-data1}

pl " Data file $FILE:"
cat $FILE

# 1FMEU64    --BBBB
pl " Sample results, awk with FIELDWIDTHS, first pattern only:"
awk '
BEGIN	{ FIELDWIDTHS = " 24 11 80" ; print "FIELDWIDTHS =", FIELDWIDTHS }
$2 ~ /1FMEU64/	{ print ; $2 = "BBBB" ; l = length($3) 
					printf("%24s%-11s%-*s\n",$1,$2,l,$3) }
' $FILE

exit 0

% ./s4

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.32-5-686, i686
Distribution        : Debian GNU/Linux wheezy/sid 
GNU bash 4.1.5
GNU Awk 3.1.7

-----
 Data file data1:
3FADP4CJ6BM103485FP8FC022FMDK38C39B2010-08-212010-10-20
4M2EU38807UJ02689VT0ZD0M1FMEU64    2008-02-292010-12-27
1FMEU64E39UA36544NS1CD0M5LMFU275   2009-07-042010-12-21
1FAHP2EW0AG131631OQ9AA1A1ZVHT82H28 2010-01-162010-12-21
1FMEU3BE6AUF00576ER9AA1A           2010-08-072010-12-23
1FMEU33E18UB03690FR9AA1A           2008-11-082010-12-23

-----
 Sample results, awk with FIELDWIDTHS, first pattern only:
FIELDWIDTHS =  24 11 80
4M2EU38807UJ02689VT0ZD0M1FMEU64    2008-02-292010-12-27
4M2EU38807UJ02689VT0ZD0MBBBB       2008-02-292010-12-27