w3schools seems to be mainly focused on using JS within a web browser.
I'm experimenting to see if JS can be used as a general-purpose
scripting language like perl, ruby, python, bash, etc. Judging from
my Googling, I am suspecting that it cannot, or at least not easily.
The biggest challenge seems to be anything system oriented: file I/O,
system calls, DB connections, etc.
Simple stuff seems to work well enough. For example, this works:
$ js -e 'print("Hello, world");'
Hello, world
As does this when saved as hw.js and permissions changed to +x:
$ cat hw.js
#!/usr/bin/env js
print("Hello, world") ;
$ ./hw.js
Hello, world
But there does not seem to be any JS way of doing the equivalent of this:
#!/usr/bin/env perl
open(FOO, "seq 1 10|") ;
@lines=<FOO>;
chomp(@lines) ;
print join("\t", @lines)."\n" ;
Or is there?
Regards,
- Robert
On Thu, Mar 26, 2009 at 2:07 PM, Don Ellis <[email protected]> wrote:
> Check out this series (unit on JS):
> http://www.w3schools.com/js/default.asp
>
> I've played around with some of their other tutorials, and was fairly
> impressed, though I'd like to go a bit deeper. Nice thing about the
> tutorials is they are hands on and live. Type in a CSS or HTML (or JS)
> expression, and it's evaluated right there.
> Let me know what you think.
> --Don Ellis
>
>
> On Thu, Mar 26, 2009 at 1:54 PM, Robert Citek <[email protected]>
> wrote:
>>
>> Can anyone recommend a good tutorial for using JavaScript at the command
>> line?
>>
>> Most JavaScript (JS) tutorials are written for using JS within a
>> browser. But JS can also be used from the command line if you install
>> the stand-alone JS interpreter Spidermonkey:
>>
>> $ sudo apt-get install spidermonkey-bin
>>
>> The canonical simple example:
>>
>> $ js -e 'print("Hello, world") ;'
>> Hello, world
>>
>> And a simple line numbering loop:
>>
>> $ yes "Hello, world" | head | js -e 'var count=0 ; while
>> (line=readline()) { count++ ; print(count, ": ", line) ; } '
>> 1 : Hello, world
>> 2 : Hello, world
>> 3 : Hello, world
>> 4 : Hello, world
>> 5 : Hello, world
>> 6 : Hello, world
>> 7 : Hello, world
>> 8 : Hello, world
>> 9 : Hello, world
>> 10 : Hello, world
>>
>> Unfortunately, it took me a bit of digging and guessing to find out
>> how to do even those simple examples. For example, the readline()
>> function isn't even mentioned in the "Javascript: the Definitive
>> Guide" book. I stumbled upon that by looking at this Mozilla page:
>>
>> https://developer.mozilla.org/en/Introduction_to_the_JavaScript_shell
>>
>> What I'm looking for is more in line with this tutorial on awk, a
>> series of one- or two-liners that get across the basic functionality
>> of the language:
>>
>> http://www.vectorsite.net/tsawk_1.html#m2
>>
>> I'm still Googling, but can anyone recommend a good JS or Spidermonkey
>> tutorial?
>>
>> Regards,
>> - Robert
>
>
> >
>
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