#!/usr/bin/env bash

# @(#) s1	Demonstrate join.

# 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 join
set -o nounset

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

# Sample data files.
pe
specimen $FILE1 $FILE2 expected-output.txt
# edges $FILE1 3
# pe
# edges $FILE2 3
# pe
# edges expected-output.txt 3

# Section 2, solution.
pl " Results:"
db " Section 2: solution."
join -t: -1 1 -2 2 -o 2.2,2.1,2.2,2.3 <( sort -t: $FILE1 ) <( sort -t: -k2,2 $FILE2 ) |
sed -e 's/:/ /' |	# first separator only
tee f1


# Section 3, post-solution, check results, clean-up, etc.
v1=$(wc -l <expected-output.txt)
v2=$(wc -l < f1)
pl " Comparison of $v2 created lines with $v1 lines of desired results:"
db " Section 3: validate generated calculations with desired results."

pl " Comparison with desired results:"
if [ ! -f expected-output.txt -o ! -s expected-output.txt ]
then
  pe " Comparison file \"expected-output.txt\" zero-length or missing."
  exit
fi
if cmp expected-output.txt f1
then
  pe " Succeeded -- files have same content."
else
  pe " Failed -- files not identical -- detailed comparison follows."
  if diff -b expected-output.txt f1
  then
    pe " Succeeded by ignoring whitespace differences."
  fi
fi

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
join (GNU coreutils) 6.10

Whole: 5:0:5 of 2 lines in file "data1"
123-23456-2341
783-ueu72-k812

Whole: 5:0:5 of 3 lines in file "data2"
linenumber1-sometext:123-23456-2341:another text
linenumber2--sometext:637-7288-ju18:some other text
linenumber3--sometext:783-ueu72-k812:some more text

Whole: 5:0:5 of 2 lines in file "expected-output.txt"
123-23456-2341 linenumber1-sometext:123-23456-2341:another text
783-ueu72-k812 linenumber3--sometext:783-ueu72-k812:some more text

-----
 Results:
123-23456-2341 linenumber1-sometext:123-23456-2341:another text
783-ueu72-k812 linenumber3--sometext:783-ueu72-k812:some more text

-----
 Comparison of 2 created lines with 2 lines of desired results:

-----
 Comparison with desired results:
 Succeeded -- files have same content.