Shell Programming and Scripting

awk '{ gsub("H", "Z", $3); 
       gsub("s", "W", $3); 
       gsub("e", "x", $3); 
       print$0}' filename

while read line;do
set $line
str=${1}" "${2}
tmp=`echo ${3}|sed 's/H/Z/g;s/s/W/g;s/e/x/g;'`
str=${str}" "${tmp}" "${4}
echo ${str}
done < yourfile

while(<DATA>){
	my @tmp=split;
	$tmp[2]=~tr/Hse/ZWx/;
	print join " ",@tmp;
	print "\n";
}
__DATA__
Dog Cat House Mouse
Dog Cat House Mouse
Dog Cat House Mouse
Dog Cat House Mouse

awk 'BEGIN{ w["H"]="Z"; w["s"]="W"; w["e"]="x"}
{ for(i in w){ gsub( i,w[i],$3) }} 1' file