sed: sed 4.2.1 (Text stream editor)  
sed:  
sed: A stream editor is used to perform basic text transformations on an input 
sed: stream (a file or input from a pipeline). While in some ways similar to 
sed: an editor which permits scripted edits (such as ed), sed works by making 
sed: only one pass over the input(s), and is consequently more efficient. But 
sed: it is sed's ability to filter text in a pipeline which particularly 
sed: distinguishes it from other types of editors.  
sed: 
sed: 
sed:  
