groff: add page (#1478)

pages/common/groff.md

@@ -0,0 +1,24 @@
+# groff
+
+> Typesetting program that reads plain text mixed with formatting commands and produces formatted output.
+> It is the GNU replacement for the `troff` and `nroff` Unix commands for text formatting.
+
+- Render a man page as plain text, and display the result:
+
+`groff -man -T utf8 {{manpage.1}}`
+
+- Render a man page using the ASCII output device, and display it using a pager:
+
+`groff -man -T ascii {{manpage.1}} | less`
+
+- Render a man page into an HTML file:
+
+`groff -man -T html {{manpage.1}} > {{page.html}}`
+
+- Process a roff file using the `tbl` and `pic` preprocessors, and the `me` macro set:
+
+`groff -t -p -me -T utf8 {{foo.me}}`
+
+- Run a `groff` command with preprocessor and macro options guessed by the `grog` utility:
+
+`eval "$(grog -T utf8 {{foo.me}})"`