stream editor for filtering and transforming text

-n, --quiet, --silent

       suppress automatic printing of pattern space

If no -e, --expression, -f, or --file option is given, then the first non-option argument is taken as the
sed script to interpret.  All remaining arguments are names  of  input  files;  if  no  input  files  are
specified, then the standard input is read.

-u, --unbuffered

       load minimal amounts of data from the input files and flush the output buffers more often

-f script-file, --file=script-file

       add the contents of script-file to the commands to be executed