Hi

This is the same question you posted in:

Need help regarding replacing a part of string

Please folow the forum rules and do not multiple post....

however...following examples should help you on your way a little:

#  mainstr="abacus sabre"
#  echo $mainstr
abacus sabre

#  echo $mainstr | sed 's/ab/cd/g'
cdacus scdre
#  echo $mainstr
abacus sabre

#  mainstr=`echo $mainstr  | sed 's/ab/cd/g'`
#  echo $mainstr
cdacus scdre