I am not much of a web developer, so apologies in advance for this dumb question.
I have a test server (Centos 6.3) with LAMP set up for me to play around. From what I understand, the server executes whatever is in /var/www/html directory. How do you edit source files in that directory ? Do you do a sudo vim "foo.php" each time you want to fix something (or add something ) ? I'd imagine that would be a pain when you are building a complex application with many files and directories .
You should change the permissions of that directory (with chmod) so you have write permissions, and can then read and write to that directory. Then, you don't need sudo.
dude. read up on version control and source code control systems like subversion and git. the idea is to develop on your machine, revision control the result, then deploy a known working version on the production server.
I use a FTP client (FileZilla) to download files, edit them and then re-upload them. If you're a one (wo)man show, and on a test setup and just playing around to learn, this is probably sufficient. With more than 1 person, or going to a (test and) production setup, you should look at some more control with svn like @Markus mentioned in another answer.
There are many approaches to modifying and deploying websites/web apps.
CentOS 6 is, by default, accessible with SSH2 on port 22. If you are on Windows you can use a combination of PuTTY and WinSCP (to manage your server, and its files, respectively). If you're on Linux or Mac OS X, SSH is already built into your system and can be accessed with Terminal. I find that using SSH is favourable over other methods because of how widely supported, secure and lightweight it is.
You'll also need a decent text editor or IDE to edit the files if you want proper syntax detection. There's tons of choices, my favourites are Notepad++ and Sublime Text 2. Not to say that I haven't edited my PHP files from time to time using the nano text editor package directly in PuTTY (yum install nano).
If you're using a edit-save-upload approach, just remember to back up your files regularly, you will find out the hard way if you fail to do so. Also, never use root unless you need to. Creating a user solely to modify your websites is good practice (adduser <username>, and give that user write access to /var/www/html).
To answer your second question:
Once you get into heavier web development you will probably want to use something like Git. Deploying with git is beyond the scope of this question so I won't get into that. In brief, you can set it up so your development environment sits locally and you can use a combination of git commit and git push to deploy.
This is what worked for me. For the record this is a Centos 6.3 server running LAMP (On Rackspace).
First, I found out that apache runs as user "apache" and group "apache" on centos systems. In other distros, I believe it runs as "www-data" in group "www-data". You can verify this by looking at /etc/httpd/conf/httpd.conf. We need to change ownership of /var/www to this user. Replace "apache" below with "www-data" if that is the case for you.
chown -hR apache:apache /var/www
Now lets make it writable by the group:
chmod -R g+rw /var/www
Add yourself to the apache group:
usermod -aG apache yourusername
Replace apache with www-data in the above if thats the case for you.
Now log out and log in - you can now edit the files, ftp them to this directory or do whatrever you want to do.
Comments welcome. TNX!