Hi all
I am new babie to shell script, so please advise me n help me .

suppose i have a string "abacus sabre", i need to replace occurences 'ab' with 'cd' and i need to store this result into same string and i need to return this result from script to the calling function, where as the string is passed from calling function.

i tried like this

mainStr="abacus"
old_word="ab"
new_word="cd"
result=`sed -i s/$old_word/$new_word $mainstr `
return $result