Search and replace with ed
ed can be used in place of sed to modify a file directly.. The format is straightforward if you have an example. Here is an example that changes the mailquota size for Maildir++.
# cat maildirsize s8909889098 # ed maildirsize << EOF > ,s/s[0-9]+ /s552428800 /g > wq > EOF # cat maildirsize s552428800 #
Inject search result into replacement string
What if you want to put the results of the last search back into the
string. You can use the ‘&’ symbol for that.
# cat test this is test # ed test << EOF > ,s/is/& a/g > wq > EOF # cat test this is a test