Shell Programming and Scripting

$ awk 'BEGIN{FS="|";}NR==FNR{a[$1$2]++;next}!a[$1$2]' file2 file1
awk: syntax error near line 1
awk: bailing out near line 1
$

diff file1.txt file2.txt 

2d1 
< HOME|NEWPORT STREET|1||NEW LISTING 
5c4 
< CAR|TOYOTA|4||NEW LISTING 
--- 
> CAR|TOYOTA|5||NEW LISTING 
6a6 
> CAR|HONDA|4||NEW LISTING

diff file1.txt file2.txt | grep ">" | cut -b 3- > add.txt

diff file1.txt file2.txt | grep "<" | cut -b 3- > drop.txt

cat add.txt 
CAR|TOYOTA|5||NEW LISTING 
CAR|HONDA|4||NEW LISTING 

cat drop.txt 
HOME|NEWPORT STREET|1||NEW LISTING 
CAR|TOYOTA|4||NEW LISTING

#!/usr/bin/env bash

# @(#) s1	Demonstrate comparison and extraction of small differences.

# Section 1, setup, pre-solution.
# Infrastructure details, environment, debug commands for forum posts. 
# Uncomment export command to run script as external user.
# export PATH="/usr/local/bin:/usr/bin:/bin"
set +o nounset
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
LC_ALL=C ; LANG=C ; export LC_ALL LANG
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
edges() { local _f _n _l;: ${1?"edges: need file"}; _f=$1;_l=$(wc -l $_f);
  head -${_n:=3} $_f ; pe "--- ( $_l: lines total )" ; tail -$_n $_f ; }
C=$HOME/bin/context && [ -f $C ] && $C specimen diff awk
set -o nounset

FILE1=${1-data1}
shift
FILE2=${1-data2}

# Display sample data files.
pe
specimen $FILE1 $FILE2 
# edges 3 $FILE1
# edges 3 $FILE2

# Section 2, solution.
pl " Preparation and pipeline:"
db " Section 2: solution."
diff -u $FILE1 $FILE2 |
tee f1 |
awk '
/^-[^-]/	{ 
			# print "debug for + working on",NR,$0
			previous = NR ; action = "deleted"; line = $0  ;  next }
/^+[^+]/	{
			# print "debug for - working on",NR,$0
				action = "inserted"
			if ( previous != NR-1 ) { 
				if ( previous != 0 ) {
				print action, $0 
				previous = 0
				next
				} else {
				print action, $0 ;
				}
		} else {
			action = "changed"
		  print action, $0
		  previous = 0
		}
		next
		}
previous != 0	{
				# print "debug for not +-",NR,$0
				print action, line ; previous = 0 }
' |
tee f2 |
awk '
/^deleted/	{ sub(/^deleted [-]/, "") ; print > "f.deleted" ; next }
/^(changed|inserted)/	{ sub(/^(changed|inserted) [+]/,"") ; print > "f.changed" ; next }
'

pl " Results, deletions file:"
cat f.deleted
pl " Results, insertions and changes file:"
cat f.changed

exit 0

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
bash GNU bash 3.2.39
specimen (local) 1.17
diff (GNU diffutils) 2.8.1
awk GNU Awk 3.1.5

Whole: 5:0:5 of 8 lines in file "data1"
HOME|ALICE STREET|3||NEW LISTING
HOME|NEWPORT STREET|1||NEW LISTING
HOME|KING STREET|5||NEW LISTING
HOME|WINSOME AVENUE|4||MODIFICATION
CAR|TOYOTA|4||NEW LISTING
CAR|FORD|4||NEW LISTING
COMPUTER|HP|1||NEW LISTING
COMPUTER|APPLE|1||NEW LISTING

Whole: 5:0:5 of 8 lines in file "data2"
HOME|ALICE STREET|3||NEW LISTING
HOME|KING STREET|5||NEW LISTING
HOME|WINSOME AVENUE|4||MODIFICATION
CAR|TOYOTA|5||NEW LISTING
CAR|FORD|4||NEW LISTING
CAR|HONDA|4||NEW LISTING
COMPUTER|HP|1||NEW LISTING
COMPUTER|APPLE|1||NEW LISTING

-----
 Preparation and pipeline:

-----
 Results, deletions file:
HOME|NEWPORT STREET|1||NEW LISTING

-----
 Results, insertions and changes file:
CAR|TOYOTA|5||NEW LISTING
CAR|HONDA|4||NEW LISTING