Shell Programming and Scripting

#!/usr/local/bin/dash
# MUTABLE! ;o)
# 'dash' Version 0.5.9

/bin/echo 'ab
b c
c$d
de
e \f\n
f/g
g~ h
h*i
i#j
j%k
kl
lm' > /tmp/array.txt

# *******************************************
# The main array generator,,,
INDEX=0
while IFS=$'\n' read -r ARRAY
do
	eval "MY_ARRAY${INDEX}='${ARRAY}'"
	INDEX=$(( INDEX+1 ))
done < /tmp/array.txt
# *******************************************

LENGTH=${INDEX}
/bin/echo "Array_length = ${LENGTH}"
# Basic test.
/bin/echo "Original array index 4 = ${MY_ARRAY4}"
MY_ARRAY4='1 2 3'
/bin/echo "Modified array index 4 = ${MY_ARRAY4}"
/bin/echo ""

INDEX=0
while [ ${INDEX} -le 12 ]
do
	eval /bin/echo "\${MY_ARRAY${INDEX}}"
	INDEX=$(( INDEX+1 ))
done

#!/usr/local/bin/dash
# IMMUTABLE! ;o(
# 'dash' Version 0.5.9

/bin/echo 'a b,bc,cd \f\n,de,ef,f g,gh,h\i,ij,jk,kl,lm' > /tmp/array.txt

ARRAY=$( cat /tmp/array.txt )

orig_ifs="$IFS"
IFS=','

set -- $ARRAY

INDEX=1
while [ ${INDEX} -le 12 ]
do
	eval VAL=$( /bin/echo "\${${INDEX}}" )
	printf "%u = %s\n" "${INDEX}" "${VAL}"
	INDEX=$(( INDEX+1 ))
done
LENGTH=$(( INDEX-1 ))

#*Just basic tests.
/bin/echo ""
/bin/echo "Array_length = ${LENGTH}"
INDEX=10
eval /bin/echo "\${${INDEX}}"
INDEX=3
eval /bin/echo "\${${INDEX}}"
/bin/echo ""

IFS="$orig_ifs"

#!/bin/dash
var="one|test|program"
oldIFS=$IFS
IFS="|"
set -- $var
echo "$1"
echo "$2"
echo "$3"      # more $9 == curly braces e.g. "${10}"
IFS=$oldIFS

#!/usr/local/bin/dash
set -- a b c
array() {
  _pos=$1
  _newval=$2
  _ARRAY= _i=-1 _val=
  shift 2
  for _val in "$@"
  do
    if [ $((_i+=1)) = $_pos ]; then
      _ARRAY="${_ARRAY}${_newval}
"
    else
      _ARRAY="${_ARRAY}${_val}
"
    fi
  done 
}

array 1 foo "$@"
oldIFS=$IFS
IFS="
"
set -- ${_ARRAY}

echo "Space as output field separator:
$@
"
echo "IFS as output field separator:
$*"

IFS=$oldIFS

Space as output field separator:
a foo c

IFS as output field separator:
a
foo
c