Archive for the 'Tutorial' Category

Page 2 of 2

Server time keeps resetting

Published on October 16, 2009 in Linux, SSH and Tutorial. 0 Comments Tags: , .

Last night I came across a ticket where a customers time kept resetting on their dedicated server. Typically I would fix the time by using the date command because most of issues I came across the servers were only minutes off. After reading through the clients ticket history I realized that the timezone and minutes were correct, but the hour was still off. After a nice little google search I came across a post on a popular linux forum, where a member had the same issue the client was having. In the post a member suggested creating a symlink for /etc/localtime to point to the clients timezone in the /usr/share/zoneinfo folder. I figured it was worth a shot and tried this fix out, and it worked perfectly :)

Since the client was located in Pakistan, he needed the server to be set to the Asai/Karachi time zone.

root@server [/]# ln -sf /usr/share/zoneinfo/Asia/Karachi /etc/localtime

Before the symlink the time showed in EST but listed the timezone as GMT +5

root@server[/]# date
Mon Jan 26 02:46:24 GMT+5 2009
root@server[/]#

After the symlink the time showed in Asia/Karachi (or GMT +5)

root@server [/]# date
Mon Jan 26 12:48:14 PKT 2009
root@server[/]#

Your localtime file should look like this now:

lrwxrwxrwx  1 root   root       32 Jan 26 12:47 localtime -> /usr/share/zoneinfo/Asia/Karachi

I’m not entirely sure why the date wasn’t correct to begin with as the timezone was correct (+5GMT) when checking with the date command. But, things are fixed now so I really can’t complain since the customer is happy :)

Hide your Shell commands

Published on October 15, 2009 in Linux, SSH and Tutorial. 0 Comments Tags: .

Today  I came across a neat, but pointless shell command. By running the following in shell, it will hide any commands you run.

root@server2 [/]# stty -echo

In order to disable this mode, simply remove the “-” before echo.

root@server2 [/]# stty echo

I guess there really is no point to the command, though you could always mess with your coworkers if they leave their shell prompt open :)

Enable PHP5 when PHP4 is default

Published on October 14, 2009 in Linux, SSH and Tutorial. 0 Comments Tags: , , , .

The following tutorial will show how to enable PHP5 on your site, when Apache has PHP4 as default. I normally do everything through SSH, so here are the steps.

root@thelinuxnoob.com [/]# cd home/thelinux/public_html/
root@thelinuxnoob.com [~/public_html]# nano .htaccess
Add the following line to the .htaccess: AddType application/x-httpd-php5 .php
ctrl + x
ctrl + y
enter
root@thelinuxnoob.com [~/public_html]# cat .htaccess | grep php5
AddType application/x-httpd-php5 .php
root@thelinuxnoob.com [~/public_html]# chmod 644 .htaccess
root@thelinuxnoob.com [~/public_html]# chown thelinux.thelinux .htaccess
root@thelinuxnoob.com [~/public_html]#

Via FTP

Open favorite text editor
AddType application/x-httpd-php5 .php
Save as “.htaccess”
Upload through FTP client

That’s my quick tutorial of the day, tune in next time for more tutorials :)

Chattr FTW!

Published on October 13, 2009 in Linux, SSH and Tutorial. 0 Comments Tags: , , .

I’m tired of clients breaking their sites and then complaining about it saying it’s an issue with the server, when in reality it’s 100% their fault to begin with. I’ve ran into a few issues where clients needed something set in their php.ini or .htaccess in order for their site to work, such as “allow_url_fopen” or “register_globals”. So to make things easier on the client I would set these variables for them and get their site working. Normally I would not hear back from the client if they left things alone, but it seems like lately the inexperienced clients have been getting the urge to modify the changes I’ve made, thus breaking their site an either getting either a 500 or some other kind of error. To prevent something like this from happening, you can go in an change the file attributes to keep them from screwing things up by using chattr. Chattr is also useful for important files on the server, as it can prevent people from removing those critical files from the server.

The letters select the new attributes for the files: append only (a), compressed (c), no dump (d), immutable  (i),  data journalling  (j),  secure deletion (s), no tail-merging (t), undeletable (u), no atime updates (A), synchronous directory updates (D), synchronous updates (S), and top of directory hierarchy (T).

Using chattr is pretty straight forward as the syntax is not too complicated. The command below would add the A and I attributes to the file, thus making it read-only so that it cannot be deleted nor modified

chattr +ai /home/clay/public_html/.htaccess

To remove the file attributes you would simply replace the “+” with “-” like so.

chattr -ai /home/clay/public_html/.htaccess

There are other attributes that can used with chattr but “AI” are the ones I commonly use. Now you can have fun using chattr to prevent clients from changing files they shouldn’t be changing.