Kwatog & Co » Linux

Suppress Error Message of cp (copy)

admin — Fri, 04 May 2012 07:34:43 +0000

There are times when you don’t need to know if the command you fired threw an error or not. That’s exactly what I needed in one of the systems I maintain. The copy command should not throw an error if there’s no file to copy. So instead of writing a number of lines for validations, I just throw the message to /dev/null. Here’s the code :

cp /path/to/file.txt /newpath/ 2> /dev/null

Source : existing codes

Remove WordPress Maintenance Mode

admin — Sat, 03 Mar 2012 16:22:39 +0000

Sometimes, upgrades fail at some point for some reason. That will leave your site in maintenance mode and unusable. That’s the “Briefly Unavailable for Scheduled Maintenance” that we see while the upgrade is on-going or if it fails. So how do we get out of the maintenance mode?

The Fix

The fix is as simple as deleting the file named .maintenance in the root folder of the site. You can delete the file via your favorite ftp or ssh client.

The Reason

During upgrade, WordPress creates a .maintenance file in the root folder. This file is removed after the upgrade is finished.

Source:
WordPress Codex

How to Get The First File in Unix

admin — Wed, 14 Dec 2011 07:20:59 +0000

In case you are looking files using ls or find command and only want to get the first file found, the command would be like.
ls -l /any/path/filename*|sed -e 's///,/g'|awk -F "," '{print $NF}'|head -1

Of course, you can also use it in find command.

find /any/path/ -name "filename*" -type f|sed -e 's///,/g'|awk -F "," '{print $NF}'|head -1

The key here is the head -1 command which limits the output to just one line. I came about this when I was investigating a problem in one of the programs that I maintain. The original code is as below.
inputFile=`ls -l /any/path/filename*|sed -e 's///,/g'|awk -F "," '{print $NF}'`
It looks correct, runs perfectly during testing and there seems to be no problem. However, if there’s more than one file, the variable inputFile will have multiple-line data. When used in a command, the problem starts. Basically, it was only expecting one file. When more than one file is push, inputFile should just get the first file. That’s why pipe-in another command which is the head -1.

In case you need the last file, then just change the head -1 to tail -1.

Bugs like this is hard to find. When we test or investigate, we usually use just one file to run through the whole program. And that’s what happened with this issue was raised to me. The previous developer is already pulling his hair because in order to get to that problematic line, he had to go trace it though a deep layer of shell scripts.

SpotVPS First Impressions

admin — Thu, 01 Dec 2011 07:57:51 +0000

After the unfortunate incident last week with NordicVPS, I decided to look for a new VPS host. As usual, I went to lowendbox and get the reviews in webhostingtalk. It’s there where I stumbled upon a promo from SpotVPS. As it turns out, SpotVPS is a low-cost VPS offering of ComfortHost.NET.

And who are they? Here’s what they say about themselves.

ComfortHost.NET have been here since 2004 offer high quality web hosting solutions. All SpotVPS nodes are fully owned hardware and are colocated. All servers used by SpotVPS have been bought with internal cash. Our only monthly cost for these servers are the actual colocation. We are financially healthy and profitable since day one. We are NOT going out of buisness any time soon. We are in it for the long run!

ComfortHost on http://www.webhostingtalk.com/showthread.php?t=1110770

Here’s the plan that I got.
$6.99/mo Ultimate Plan
Memory: 2048mb (2gb)
HD Space: 50gb (50,000mb)
Bandwidth: 1,000gb (1TB)
Monthly Price: $6.99/mo
Setup Fee: FREE!
FREE GIGABIT PORT – FREE WEEKLY BACKUPS – FREE HARDWARE RAID
Location: Orlando, FL at DimeNOC
Test IP Address: 72.29.87.105

2GB RAM for $6.99. That’s sweet. Want to try it yourself? ORDER NOW

Word of caution,though. This plan (and all other dirt-cheap vps that I know of) comes with very limited support. You are usually given your VPS, IP and OS install and you have to do the rest. I installed mine with NGiNx, PHP, MySQL and it’s already up and running for 7 days straight now.

Here’s the result of the test I made on my VPS.
[root@vps ~]# dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync 16384+0 records in 16384+0 records out 1073741824 bytes (1.1 GB) copied, 14.9939 seconds, 71.6 MB/s


[root@vps ~]# wget cachefly.cachefly.net/100mb.test

--2011-11-24 18:10:35-- http://cachefly.cachefly.net/100mb.test

Resolving cachefly.cachefly.net... 205.234.175.175

Connecting to cachefly.cachefly.net|205.234.175.175|:80... connected.

HTTP request sent, awaiting response... 200 OK

Length: 104857600 (100M) [application/octet-stream]

Saving to: `100mb.test'

100%[==============================================================================================================================>] 104,857,600 66.8M/s in 1.5s 2011-11-24 18:10:36 (66.8 MB/s) - `100mb.test' saved [104857600/104857600]

I’ll try to come up with a review together with my other hosting providers.

How To Install Setacl in Linux

admin — Sat, 30 Jul 2011 05:50:52 +0000

First, there’s no setacl in Linux. Instead, it has setfacl. Take note of the f. Second, setfacl is part of the access control list(acl) package so we install the acl intead of setfacl. In that way, we also install getfacl.

Here’s how.

yum -y install acl

Ok, that’s for CentOS and other RedHat alternatives. I believe it is sudo apt-get acl for Debian/Ubuntu flavors.

How to Upgrade MySQL 5.0 to 5.5 in CentOS

admin — Mon, 25 Jul 2011 16:19:38 +0000

I upgraded the installed MySQL on my two VPSes about two months ago and I thought I already saved the steps somewhere or at least the saved the URL of the how to. I did not so when I tried to upgrade the Pagudpud Resort‘s (owned by the Jackoleros) database server, I don’t know where to start. The MySQL official website suggests(or at least, that’s how I understand it) that I recompile. I know I did not recompile before so after some fruitless googling, I finally found a working version. But first, thanks to remi for sharing the rpm.

Before we proceed, I’d like to remind you that this is for MySQL 5.5.14 on CentOS 5.6. My original MySQL install was 5.x. If your baseline environment is different from mine, then I suggest you look elsewhere for the tutorial. The source at the end of this post may help.

**** UPDATE *****
The following steps require the EPEL (Extra Packages for Enterprise Linux) so you’ll have to install epel first before proceeding. Here’s the command:
rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm

Step 1 login as root to your vps

Step 2 Install Remi repository
rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-5.rpm
The result will something like..
Retrieving http://rpms.famillecollet.com/enterprise/remi-release-5.rpm warning: /var/tmp/rpm-xfer.cVJJxn: Header V3 DSA signature: NOKEY, key ID 00f97f56 Preparing... ########################################### [100%] 1:remi-release ########################################### [100%]

Step 3 Check availability of MySQL versions
yum --enablerepo=remi,remi-test list mysql mysql-server

the last lines of the output should be something like this.
Available Packages mysql.i386 5.5.14-1.el5.remi remi mysql-server.i386 5.5.14-1.el5.remi remi [root@one ~]#

Step 4 Update or Install MySQL
yum --enablerepo=remi,remi-test install mysql mysql-server


Step 5 Restart MySQL

service mysqld start
Step 6 Upgrade MySQL Databases

mysql_upgrade -u root -p
***** NOTE : THE LAST STEP IS VERY IMPORTANT BECAUSE IT WILL CREATE PRIVILEGE TABLES ******
Source :
http://www.if-not-true-then-false.com/2010/install-mysql-on-fedora-centos-red-hat-rhel/



LAMP Install on VPS : CentOS5+Apache+MySQL+suPHP
admin — Sun, 24 Jul 2011 15:50:14 +0000
Here’s the work-in-progress instructions for setting up a LAMP. It’s been sitting on my draft for ages and I have to publish it because a few of my friends need it. 
**** NOTE : If you notice, it’s still a draft. It came from a number of sources but these are the steps I use. So I know it works. **********

update apache

yum -y update 
install utilities and compiler

yum -y install zip nmap fileutils gcc-c++ acl
install make

yum -y install make
MySQL Installation


yum -y install mysql mysql-devel mysql-server

chkconfig --levels 235 mysqld on

mysqld start

/usr/bin/mysql_secure_installation


Install PHP
yum -y install php php-devel php-gd php-imap php-ldap php-mysql php-odbc php-pear php-xml php-xmlrpc curl curl-devel perl-libwww-perl ImageMagick libxml2 libxml2-devel



Upgrade PHP to 5.3

rpm -Uvh http://repo.webtatic.com/yum/centos/5/latest.rpm

yum --enablerepo=webtatic update php
Install ProFTP
yum -y remove vsftpd   --to remov vsftpd if it's existing

cd /tmp

wget --passive-ftp ftp://ftp.proftpd.org/distrib/source/proftpd-1.3.3e.tar.gz

tar xvfz proftpd-1.3.3e.tar.gz

cd proftpd-1.3.3e

./configure --sysconfdir=/etc; make; make install

cd /tmp; rm -rf ./proftpd-1.3.3*

ln -s /usr/local/sbin/proftpd /usr/sbin/proftpd

touch /etc/init.d/proftpd

chmod 755 /etc/init.d/proftpd

vi /etc/init.d/proftpd


Paste the following settings and then save.



#!/bin/sh

# $Id: proftpd.init,v 1.1 2004/02/26 17:54:30 thias Exp $

#

# proftpd This shell script takes care of starting and stopping

# proftpd.

#

# chkconfig: - 80 30

# description: ProFTPD is an enhanced FTP server with a focus towards

# simplicity, security, and ease of configuration.

# It features a very Apache-like configuration syntax,

# and a highly customizable server infrastructure,

# including support for multiple 'virtual' FTP servers,

# anonymous FTP, and permission-based directory visibility.

# processname: proftpd

# config: /etc/proftp.conf

# pidfile: /var/run/proftpd.pid

# Source function library.

. /etc/rc.d/init.d/functions
# Source networking configuration.

. /etc/sysconfig/network
# Check that networking is up.

[ ${NETWORKING} = "no" ] && exit 0
[ -x /usr/sbin/proftpd ] || exit 0
RETVAL=0
prog="proftpd"
start() {

echo -n $"Starting $prog: "

daemon proftpd

RETVAL=$?

echo

[ $RETVAL -eq 0 ] && touch /var/lock/subsys/proftpd

}
stop() {

echo -n $"Shutting down $prog: "

killproc proftpd

RETVAL=$?

echo

[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/proftpd

}
# See how we were called.

case "$1" in

start)

start

;;

stop)

stop

;;

status)

status proftpd

RETVAL=$?

;;

restart)

stop

start

;;

condrestart)

if [ -f /var/lock/subsys/proftpd ]; then

stop

start

fi

;;

reload)

echo -n $"Re-reading $prog configuration: "

killproc proftpd -HUP

RETVAL=$?

echo

;;

*)

echo "Usage: $prog {start|stop|restart|reload|condrestart|status}"

exit 1

esac
exit $RETVAL


vi /etc/proftpd.conf



Group nobody

DefaultRoot ~

IdentLookups off

ServerIdent on "FTP Server ready."


chkconfig –levels 235 proftpd on
Install suPHP
cd /tmp

wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm

rpm –import http://apt.sw.be/RPM-GPG-KEY.dag.txt

rpm -K rpmforge-release-0.5.2-2.el5.rf.*.rpm

rpm -i rpmforge-release-0.5.2-2.el5.rf.*.rpm

yum -y install htop

yum -y install mod_suphp

edit /etc/suphp.conf

make sure these lines are there:
webserver_user=apache

x-httpd-php=”php:/usr/bin/php-cgi”

x-suphp-cgi=”execute:!self”
 edit /etc/httpd/conf.d/suphp.conf (which is the global configuration for suPHP).

vi +/suPHP_Engine /etc/httpd/conf.d/suphp.conf
change it to suPHP_Engine off
6) Set suPHP to work with VirtualHost, add these few lines inside   tag.
suPHP_Engine on

suPHP_UserGroup username groupname

AddHandler x-httpd-php .php .php3 .php4 .php5

suPHP_AddHandler x-httpd-php
Example :



    ServerAdmin support@yourdomain.com

    DocumentRoot /usr/kitty/yourdomain.com

    ServerName yourdomain.com

    ServerAlias *.yourdomain.com

    suPHP_Engine on

    suPHP_UserGroup kitty kitty

    AddHandler x-httpd-php .php .php3 .php4 .php5

    suPHP_AddHandler x-httpd-php

    ErrorLog logs/yourdomain.com-error_log

    CustomLog logs/yourdomain.com-access_log common


Source : CentOS Additional Packages



Recursive setacl command on Linux/Unix
admin — Fri, 24 Jun 2011 09:45:35 +0000
Setting access control list(acl) recursively is not as straigthforward in HP/UX. I believe the same is true for other Unix flavors. In case you are wondering how, the command is shown below.





find /any/path -exec setacl -m user:USERID:rwx {} ';'


What it does is it finds all the files and directories inside the /any/path, recursively. And then on each of the files/directories, it executes the the setacl command. 
For some linux flavors, this is done simpler as below.



setacl -Rm user:USERID:rwx


Here’s how to install setacl/setfacl –>Install setacl



SubVersion Initialization Error
admin — Mon, 13 Jun 2011 08:00:37 +0000
After installing subversion, I hit some error when I tried to restart Apache. When I removed/renamed the subversion.conf and the error went away. Obviously, subversion did not work. So I investigated to find out the root cause.



Here’s two of the errors I encountered.

Cannot load /etc/httpd/modules/mod_dav_svn.so
Invalid command ‘AuthUserFile’

Solution
Uncomment the following lines in httpd.conf



LoadModule dav_svn_module     modules/mod_dav_svn.so

LoadModule authz_svn_module   modules/mod_authz_svn.so


It turned out that I commented these files to limit the number of modules loaded on Apache. I’m only loading the bare minimum so that WordPress would run properly on my VPS.



How To Install Subversion on CentOS
admin — Sun, 12 Jun 2011 20:00:12 +0000
I finally decided to setup an online version control and chose subversion (instead of cvs which I use on my macbook). Initially, I was thinking of subscribing to github but the prospect of paying monthly did not bode well especially that it would only be me who will be updating the codes. Github has a free service though. But that’s if you open-source your code.



Ok, enough for the chatter. Here’s the steps for installing subversion.
Step 1: Install SubVersion via yum

yum install mod_dav_svn subversion
Step 2: Edit Apache Config

vi /etc/httpd/conf/httpd.conf
make sure to uncomment the following lines.

LoadModule authn_file_module modules/mod_authn_file.so

LoadModule dav_module modules/mod_dav.so


Step 3: Restart Apache

service httpd start
Step 4: Edit subversion.conf



cd /etc/httpd/conf.d/

vi subversion.conf



make sure the modules below are also uncommented

LoadModule dav_svn_module     modules/mod_dav_svn.so

LoadModule authz_svn_module   modules/mod_authz_svn.so
Add the following to allow a basic authentication and point Apache to where the actual repository resides.





   DAV svn

   SVNParentPath /var/www/svn/repos

   # Limit write permission to list of valid users.

   

      # Require SSL connection for password protection.

      # SSLRequireSSL
      AuthType Basic

      AuthName "Authorization Realm"

      AuthUserFile /etc/svn-auth-conf

      Require valid-user

   




VPS ALERT!!!!

Since I’m using Virtual Private Server (VPS) and suPHP, I have the code below. Take note that the location is inside the VirtualHost directive.





    ServerAdmin support@domain.com

    DocumentRoot /var/www/domain.com

    ServerName domain.com

    ServerAlias *.domain.com

    suPHP_Engine on

    suPHP_UserGroup myuser myuser

    AddHandler x-httpd-php .php .php3 .php4 .php5

    suPHP_AddHandler x-httpd-php

    ErrorLog logs/domain.com-error_log

    LogFormat "%h %l %u %t "%r" %>s %b" common

    CustomLog logs/domain.com-access_log common

    

      DAV svn

      SVNParentPath /var/www/domain.com/repos      SetHandler repos

     

      AuthType Basic

      AuthName "Authorization Realm"

      AuthUserFile /etc/svn-auth-conf

      Require valid-user

    
>





Step 5: Set the Password for your Users



[root@vps ~]# htpasswd -cm /etc/svn-auth-conf yourusername

New password:

Re-type new password:

Adding password for user yourusername

[root@vps ~]# htpasswd -m /etc/svn-auth-conf anotherusername

New password:

Re-type new password:

Adding password for user anotherusername


Step 6: Create Your Repository



[root@vps ~]# cd /var/www/ -- Or wherever you placed your path above

[root@vps ~]# mkdir svn

[root@vps ~]# cd svn

[root@vps ~]# svnadmin create repos

[root@vps ~]# chown -R apache:apache repos

[root@vps ~]# service httpd restart



Source : http://wiki.centos.org/HowTos/Subversion