improve

textproc/gsed/DESCR

@@ -1 +1,8 @@
-This is GNU implementation of the POSIX stream editor `sed'; see sed(1).
+GNU implementation of the POSIX stream editor `sed'.
+
+Sed (streams editor) isn't really a true text editor or text
+processor. Instead, it is used to filter text, i.e., it takes text
+input and performs some operation (or set of operations) on it and
+outputs the modified text. Sed is typically used for extracting part
+of a file using pattern matching or substituting multiple occurances
+of a string within a file.