perl script using XML parser to read values in text file and replace it xml file

my @massipaddr = map { $_->{IPAddress} } @{ $peermas->{Appliance} };

@ECHO OFF
SETLOCAL ENABLEDELAYEDEXPANSION
TYPE NUL>tempOutput.xml
SET line=0
SET from=
SET to=
FOR /F %%a IN (a.txt) DO (
    IF !line!==0 SET from=%%a
    IF !line!==1 SET to=%%a
    SET /a line=!line!+1
)
ECHO replacing %from% with %to%...
FOR /F %%a IN (a.xml) DO (
    SET currentLine=%%a
    SET currentLine=!currentLine:%from%=%to%!
    ECHO !currentLine!>>tempOutput.xml
)
DEL /q a.xml
MOVE tempOutput.xml a.xml
PAUSE

export ALERT_LEVEL=DANGER
export NORMAL_LEVEL=NORMAL
export RELAX_LEVEL=RELAX

sed file1.json -e 's/$ALERT_LEVEL/DANGER/g' -e's/$NORMAL_LEVEL/NORMAL/g' -e's/$RELAX_LEVEL/RELAX/g' >file2.json

#!/bin/bash

WORD="foo" # what to find
TXT_FILE="/tmp/lala.txt" # where

# get the new word from user
read -p "With what \"$WORD\" should be replaced ? " newword

# replace, preserving capitalization
output=$(cat "$TXT_FILE" | sed "s/${WORD^}/${newword^}/g" | sed "s/$WORD/$newword/ig")
echo "$output" > "$TXT_FILE"
echo "done"

/tmp » cat lala.txt 
Foo is riding a bike, while Frank is sunbathing. 
Suddenly, Foo falls. And also Foo, foo, foo.

/tmp » ./lala.sh     
With what "foo" should be replaced ? bar
done

/tmp » cat lala.txt 
Bar is riding a bike, while Frank is sunbathing. 
Suddenly, Bar falls. And also Bar, bar, bar.