What does “@” mean in makefile?

Question

We offen use @echo "do..." to letting to print only do... . But who can tell me what is the mean of this condition ?

COUNT=$(shell ls | wc -l )

Then

@COUNT=$( shell ls | grep abc | wc -l )

What's the mean of the second?

Answer 1

It disables printing the command line being executed. Any output from the command itself still appears. See this previous question or see this Makefile reference.

Answer 2

It will hide the output of the commandline when executing. Normally each command, when executing a rule, is printed to the console. This will suppress this output.