use the 1st argument, or, if none is present, standard input
use the 1st argument, or, if none is present, standard input
Sometimes you want to write a tool that takes a filename as its argument. However, if there is no argument provided, it'd be great to also accept it on standard input.
Let's write a simple version of the program cat
:
cat.js
var arg = require('argv-or-stdin')
var fs = require('fs')
arg(function (err, filename) {
fs.createReadStream(filename)
.pipe(process.stdout)
})
And test it:
$ cat > test
hello warld
^D
$ node cat.js test
hello warld
$ echo 'test' | node cat.js
hello warld
var arg = require('argv-or-stdin')
A function that will check process.argv[2]
and, if it does not exist,
accumulate all of process.stdin
into a string and return that.
cb
is a callback function of the form function (err, name) {}
.
With npm installed, run
$ npm install argv-or-stdin
ISC