// filter
// node 4-filter.js path subname
var fs = require("fs")
var dir = process.argv[2]
var subname = process.argv[3]
var path = require("path")
// get files list in dir
fs.readdir(dir, function(err, list) {
// if path.extname = subname
// log it
for(i=0; i<=list.length; i++){
if(path.extname(list[i]) == ("."+subname) ){
console.log(list[i])
}
}
} );