unix shell中echo和@echo之间的区别

Question

What's the difference between "echo" and "@echo" in the unix world?

I can't even google special characters.

For example, as used here

Answer 1

That's a Makefile-specific thing ; it has nothing to do with shell scripts.

Recipes that begin with @ do not echo the command. That is to say, with a Makefile

foo:
    echo foo

You get

$ make foo        # <-- this is meant to be the command you enter in the shell
echo foo
foo

Whereas with a Makefile

foo:
    @echo foo

it is

$ make foo
foo

Answer 2

applemcg.$ fbdy newest trace_any
function newest
{ 
    trace_call $# $*;
    [[ -f "$1" ]] || { 
        trace_call NO $1;
        return 1
    };
    t=$1;
    shift;
    while [[ -n "$1" ]]; do
        [[ "$t" -ot "$1" ]] && { 
            trace_call NEWER $1 than $t;
            return 1
        };
        shift;
    done;
    trace_call NEWEST $t;
    return 0
}
function trace_any
{ 
    printf $* 1>&2
}
applemcg.$ 

so, the "make paradigm" is

newest outputfile inputa inputb... || {

      command input...   > outputfile
}

and you cat toss your makefiles on the scrap heap of history.