sed output file code example

Example 1: sed output to file

sed 's/Hello/Hi/g' file-name > file

Example 2: sed output of command

Just use something like following with p option at sed command`s end:
cat file.txt| sed -En "s/string_to_replace/replacement_string/p"

Example 3: gsed comand store file

sed -i 's/Hello/Hi/g' file-name