PHP and Shell scripts

aashoo_5

Hi All

Can PHP call Unix Shell scripts
If yes , can I have some sample code on how to call shell scripts
and how to do error handling in that

Thanks
Ashwin N.

Threehearts

Hi Ashwin!

What youre looking for is LXXXIII. Program Execution functions in the PHP Manual
http://www.php.net/manual/en/ref.exec.php

greetings,
Jakob

aashoo_5

Thanks Jakob.
But I dont understand.
My PHP will be running under windows in a browser
AND how do I communicate with UNIX environment.
How will it know the ip ADDRESS ETC ETC

Thanks
Ashwin N.

Threehearts

Ah, wait.
php is SERVERSIDED...
so if the server is *nix php will execute there and of course there the shell commands do work...

unless your webserver is buggy no php will ever reach the client... at least it should not.

what happens (or should at least) is that you send requests to the server, usually via http, and php works upon this request. so it doesn't matter what the client is because all it has to do is pack the data php requires and send it to the server.

the client does NOT have to process anything - that would be clientsided and is what JavaScript or other clientsided scripts do.

you have always to keep in mind where the action actually happens.

i hope this helps you and i didnt misunderstand your question from the beginning.

example for how it works:

client: (html/javascript/...)

<form>
....formdata, modified by clientsided script
</form>

--> submit action

--> request with data sent to server

server (php/perl/...)

takes formdata (
URL?var_name=somevalue
becomes
$var_name = "somevalue";

--> php engine works and calculates answer to request while for example calling a shell script

--> webserver sends answer to request (usually html, wml or something the client understands) to client

--> client displays answer

if you want to see what happens if this goes wrong play around with headers of output files a little, especially if you use xml/xhtml definitions...

i hope this makes clear what happens where....

as i said, i hope i had your question right in the first part. if not so i apologize and ask to further explain your question...
it's quite possible that i'm more than a little dumb now and then.
lauchs

greetings, jakob

aashoo_5

Thanks for the answer Jakob.
Does this mean PHP resides on the webserver
If Yes then again my webserver and Unix server will be totally different. Right ?

Please pardon my lack of knowledge since I am new to this stuff

Thanks
Ashwin N.

Threehearts

Basically, yes.
In a web-context the php engine is controlled by your webserver(ie. software), which in turn is running in the environment (eg. *nix) of the server (hardware).

Out of practical needs the engine can work not only with the webserver software but - to some extent - also directly with the server environment - nix or win for example.
eg if you save some data to files or want to log what happens on your website in a logfile (always a good idea) you obviously have to interact directly with the filesystem (fopen and this stuff).

So youre quite right, php engine and server environment are apart from each other but they do interact.

Because of that whatever happens the client, sitting on the other end of telephone line, SHOULD NOT be able execute serversided script commands directly - therefor he can't, usually.

Of course there are hacks around that - not properly configured webserver, engine or other holes that you open up yourself...
if you eval userinput directly without checking the content for one, the data the client sends might become executional commands under certain circumstances...

but: by itself the client has got NO direct access to the ss (serversided) script engine and therefor can't do as he pleases.
good thing also, that.

so things basically either happen on the server - thats php, asp, cgi or something similar - or it happens on the client.

think in request - answer categories, works best most of the time.

i hope that explained something.
greetings, jakob

aashoo_5

Thanks a LOT , JAKOB.
That really helped.
I wonder if you could give me a link which explains
how the web technolgies work . ie Webserver interacting with client and server etc etc.
As you see I am a total newbie

Threehearts

hmm...
if you by chance speak german i'd recommend http://selfhtml.teamone.de
- best resource for all the basic stuff that i've ever seen

in english - dont know.
There should be plenty of material around, just keep away from anything like "HTML 4.0 for Dummies" - those wont give you what you want.

Altime favorite of course is O'Reilly Books - Theyve got several books available online.

devedge.netscape.com has been around for a while also - that's the developers corner of netscape - they started it in the days when they fought their browser war vs. microsoft... grin

i'd also have a look into usenet, there should be newsgroups around where you get to know about everything you might want to in this area.

if i can answer any other question, ask.
good to be useful for once. grin
greetings, jakob

aashoo_5

Thanks Jakob.
that really helped.
Thaks again

Threehearts

np at all.
just dont forget to mark the thread as "solved".

🙂
j.