Streams editor. Edits one or more
files without user interaction. For more information on sed, see sed and awk (O'Reilly). The -e and -f options may be provided multiple times, and they may be used with each other.
Treat all files as text and compare them.
Apply the editing
instruction to the files.
Use extended regular expressions.
Apply the set of instructions from the editing
Edit files in place, saving the original files with
extension appended. If
extension is not specified, no backups are made.
Suppress default output.