entr: edit page (#12430)

* entr: edit page

---------

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/common/entr.md

@@ -1,7 +1,7 @@
 # entr
 
 > Run arbitrary commands when files change.
-> More information: <https://manned.org/entr>.
+> More information: <http://eradman.com/entrproject/>.
 
 - Rebuild with `make` if any file in any subdirectory changes:
 
@@ -18,3 +18,15 @@
 - Run a command with the changed file (`/_`) as an argument:
 
 `{{ls *.sql}} | entr {{psql -f}} /_`
+
+- [c]lear the screen and run a query after the SQL script is updated:
+
+`{{echo my.sql}} | entr -cp {{psql -f}} /_`
+
+- Rebuild the project if source files change, limiting output to the first few lines:
+
+`{{find src/}} | entr -s {{'make | sed 10q'}}`
+
+- Launch and auto-[r]eload a Node.js server:
+
+`{{ls *.js}} | entr -r {{node app.js}}`