https://github.com/tjfontaine/node-nf

Node Filter -- use node for one liners like you would with perl
https://github.com/tjfontaine/node-nf

Last synced: 3 days ago
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Node Filter -- use node for one liners like you would with perl

• Host: GitHub
• URL: https://github.com/tjfontaine/node-nf
• Owner: tjfontaine
• Created: 2013-06-16T02:49:27.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-07-05T03:00:01.000Z (about 11 years ago)
• Last Synced: 2024-04-15T14:25:07.924Z (6 months ago)
• Language: JavaScript
• Size: 117 KB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# nf

If you've used perl oneliners before you're expecting when you pass `-pe` to

node that you'll evaluate the script once per input line

```

$ echo -e "foo\nbar" | perl -pe '"baz"'

foo

bar

```

However if you try it:

```

$ echo -e "foo\nbar" | node -pe '"baz"'

baz

```

`nf` is a small package that lets you perform arbitrary javascript/node actions

once per input line:

```

$ npm install -g nf

$ echo -e "foo\nbar" | nf -pe '"baz"'

baz

baz

```

Valid command line arguments:

 * `-e` -- evaluate the given script (if not passed assumes last argument is

a javascript file to load)

 * `-n` -- evaluate the given script once per input line, the current line is

available in the global `__line`

 * `-p` -- evaluate the given script once per input line with an implicit print

of the return value (implies `-n`)

Here's a small example interpreting the current line

```

$ echo -e "foo\nbaz\nfoobar" | nf -pe '__line.replace(/foo/, "bar")'

bar

baz

barbar

```

Here is `apache.js` which transforms an apache log line to json:

```javascript

var pattern = /^(\S+)\s+(\S+)\s+(\S+)\s+\[(.+)\]\s+(.+)\s+(.+)\s+(HTTP\/\d+.\d+)\s+"(\d+)"\s+(\S+)\s+"(.*)"\s+"(.*)"\s+"(.*)"$/;

(function(line) {

  var m = line.match(pattern);

  if (!m) return JSON.stringify({});

  var obj = {

    host: m[1],

    a: m[2],

    user: m[3],

    date: m[4],

    method: m[5],

    url: m[6],

    version: m[7],

    statusCode: m[8],

    contentLength: m[9],

    refer: m[10],

    userAgent: m[11],

  };

  return JSON.stringify(obj);

})(__line);

```

then using [jsontool](http://npmjs.org/package/jsontool) you can find the `uniq` userAgents

```

cat access.log | nf -p ./apache.js | json -ga userAgent | sort -r | uniq | head 10

Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:21.0) Gecko/20100101 Firefox/21.0

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20100101 Firefox/21.0

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.110 Safari/537.36

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31

Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_4) AppleWebKit/536.30.1 (KHTML, like Gecko) Version/6.0.5 Safari/536.30.1

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.37 Safari/537.36

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.110 Safari/537.36

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.110 Safari/537.36

Mozilla/4.0 (compatible;)

```

## scripts

Scripts (either in string form or from a file) are not the same thing as a node

module; most but not all the globals you expect are there. You can `require` in

your script, but notably `exports` and `module` are missing as their utility

would be suspect.

## license

MIT