for i in `find -maxdepth 1 -type d`; do  echo -n $i " ";find $i|wc -l; done

I am sure there are many different ways to show file count for each folder in a directory and I am curious to see what people do so please do post comments with what you do.

Above command is pretty simple and can be expanded to do whatever you need.  For example, you can throw it into a bash script and be able to pass parameters.  For example:  count_files /home/  In this case your command line would look like:

for i in `find /home/ -maxdepth 1 -type d`; do  echo -n $i " ";find $i|wc -l; done

only difference would be that /home/ would be argument you passed and therefore will be $1.  Here is a sample script for above example:

#!/bin/bash
for i in `find $1 -maxdepth 1 -type d`; do
echo -n $i " ";
find $i|wc -l;
done

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

So without further delay, following command will telnet to local memcached server on port 11211 and issue one of the memcached commands, stats

(sleep .5;echo stats) | telnet localhost 11211
You may have to play with the sleep timer to get it to work for your environment but in our .5 was the sweet spot. Good luck and let me know if you have another shell command. Obviously we can do this from perl, php, python, etc but the beauty of this is that you do not need any other dependencies plus its a very short command.

Since “jsled” commented about nc (thanks jsled), here is the syntax to do the same thing with nc:

echo "stats" | nc localhost 11211

Assumptions:  you will be connecting as user “root” to svn server located at “10.0.0.1″.  All your files will be saved at c:\ including your svn command line utility

First we will have to generate a key.  We can accomplish this by using a free utility called puttygen.  Run puttygen and click on “Generate” button.  You will have a key similar to below example:

Example of a key generated by puttygen

Copy this, you will need it in few mins.  At this point, go ahead and create a private key by clicking on:  “Save private key”.  Save this as private.ppk on your C:\. 

Now let us log in to the svn server and add this public key to the authorized_keys2 (see setting up keys for step by step instructions).  I will assume you are using “root” as login.

vi /root/.ssh/authorized_keys2

Make sure when you paste, it is not broken into different lines.  All of the key should be one line.

Ok now back to your Windows machine.  Now we need to set up ssh tunnel to our server.  There are few ways of doing this but for our purpose, we will use another free program provided by the same developers as puttygen: download plink to C:\.  If you do not do this step, you will get following error:

svn: Can't create tunnel: The system cannot find the file specified.

Ok let us set the variables for svn.  Go to command prompt and type (you can also set this in your scripts and inside windows environment.  But since this post is to show you an example, we will just do this):

set SVN_SSH="/plink.exe" -i /private.ppk -l root

Now let’s run this one time manually to cache key:

/plink.exe -i /private.ppk -l root 10.0.0.1

Press “y” when it asks you to save.  Type exit and get back to your prompt.

Ok now we can test our svn utility.

/svn info svn+ssh://10.0.0.1/svn/testrepo/trunk/

This should display output similar to:

Path: trunk
URL: svn+ssh://10.0.0.1/svn/testrepo/trunk
Repository Root: svn+ssh://10.0.0.1/svn/testrepo
Repository UUID: b9143312-b1a1-11ba-a111-11cdcd1d2222
Revision: 10
Node Kind: directory
Last Changed Author: root
Last Changed Rev: 4
Last Changed Date: 2008-11-18 15:18:47 -0800 (Tue, 18 Nov 2008)

Now you are ready to script your checkouts, do checkin’s with out having to type in your password, etc.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

Note:  you only have to do the following installations on the server where you are doing the mounts on.

Let us download and install the filesystem framework which is a requirement for sshfs called fuse.

wget http://voxel.dl.sourceforge.net/sourceforge/fuse/fuse-2.7.4.tar.gz
tar zxpfv fuse-*.gz
cd fuse*
./configure

If you get the following error, you will either have to point to the location of the kernel source or install it if needed.

checking kernel source directory... Not found
configure: error:
*** Please specify the location of the kernel source with
*** the '--with-kernel=SRCDIR' option
configure: error: ./configure failed for kernel

In our case here, we will be installing the source using yum.

yum -y install kernel-devel

Once installed, you will have to find out the directory it is installed in

ls -l /usr/src/kernels/
total 4.0K
drwxr-xr-x 18 root root 4.0K Oct  7 14:50 2.6.18-92.1.13.el5-x86_64/

./configure --with-kernel=/usr/src/kernels/2.6.18-92.1.13.el5-x86_64
make && make install
cd ..

Now let us get sshfs source and install it.

wget http://voxel.dl.sourceforge.net/sourceforge/fuse/sshfs-fuse-2.1.tar.gz
tar zxpfv sshfs*
cd sshfs-fuse-*
./configure

If you get the following error:

checking for SSHFS... configure: error: The pkg-config script could not be found or is too old.  Make sure it
is in your PATH or set the PKG_CONFIG environment variable to the full
path to pkg-config.

OR

checking for SSHFS... configure: error: Package requirements (fuse >= 2.2 glib-2.0 gthread-2.0) were not met:

No package ‘glib-2.0′ found
No package ‘gthread-2.0′ found

You need to install glib2.  Do the following:

yum install glib2-devel

Once installation is done, continue with configure.

./configure
make && make install

After installation is done, we can move on with testing the installation:

cd /mnt
mkdir test
sshfs 10.0.0.2:/ test

If you get the following error,
sshfs: error while loading shared libraries: libfuse.so.2: cannot open shared object file: No such file or directory
execute this: NOTE: this is for x64 system. If you have 32 bit system, you have to symlink to /lib instead.
ln -s /usr/local/lib/libfuse.so.2 /lib64/
Let us try mounting again:
sshfs 10.0.0.2:/ test
At this point it would be like if you were making a ssh connection to 10.0.0.2 You will have to type in a password to get the mount to happen. You may get the following error: fuse: device not found, try 'modprobe fuse' first

If you do ‘modprobe fuse’, as they tell you to, and you get:
modprobe fuse
FATAL: Module fuse not found.

That means your running kernel is not the same version as the one you compiled with. You have two options here:
1) you can upgrade your kernel by typing: yum update kernel
2) find the source files for the kernel you have running and recompile fuse.

I went with option 1. Once you do the update, reboot and try doing modprobe fuse again.

At this point we can try doing the mount again.
cd /mnt
sshfs 10.0.0.2:/ test

If you do not get any errors, do df -h to see the mount:
...
sshfs#10.0.0.2:/ 1000G 0 1000G 0% /mnt/test
...

At this point you can browse 10.0.0.2 server filesystem as it was local on your server.

————————————-

DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

wget http://www.whatismyip.org

Well that does the trick.  But being lazy as I am, I did not want to have to cat the output file to find out the ip (plus there is no point of creating extra files and doing extra work to remove them).  So if you are ssh’ed in, you can issue following command (I am sure there is another way of doing it, but this is the quickest way I could think of):

wget -q -O - http://www.whatismyip.org

-O tells wget to redirect output to the following file (- being the standard out ).  So it basically echo’s output to our console.

-q makes wget run in  quiet mode so you do not see all of the connection/download/etc output.

That is it!  I am curious to know what other ways people use to get the same information.  Please share your way if possible.

————————————-

DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

mkdir temp
cd temp
touch Foo FooO "Foo Bar" "FOO BAaR"
\ls | while read -r FILENAME
do
mv -v "$FILENAME" `echo $FILENAME| tr ' ' '_'| tr '[A-Z]' '[a-z]'`
done

Note:  I intentionally have slash in front of ls (\ls).  \ls means that we want to make sure there is no ls alias overwriting our command. This is needed if your system has alias setup to display ls in a different way instead of default listing.  mv -v shows us the filenames being renamed as your script goes through the whole dir.  Your output should be like:

`Foo' -> `foo'
`FOO BAaR' -> `foo_baar'
`Foo Bar' -> `foo_bar'
`FooO' -> `fooo'

One of the very powerful commands in this post is the “tr” command. This command is not as popular as sed or awk but it is very useful and simple to use (read more about tr).

If you only needed to convert spaces to underscores and you are using CentOS/Fedora/Redhat, you can use this simpler method. NOTE: this command is not available on all distributions: rename " " "_" *

Learn more about rename command
————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

Note: you must be logged in as root to do following.

vi /etc/passwd
find joe and change it to john, save/exit

vi /etc/group
find joe and change it to john, save/exit

vi /etc/shadow
find joe and change it to john. This file is read only and you have to force overwrite it. In vi it is :w! once saved, quit.

cd /home
mv joe john

And that should do the trick.

[Edited] Right after I posted this post, I was contacted and was told to look at utility called usermod. Read more about it man usermod. Got to love the quick responses.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

When Linux server boots up, it calls a program called mingetty. This program creates that infamous login prompt as show in a screenshot:

You can see how server calls the mingetty program by looking at /etc/inittab. You will see a block like below:

# Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6

When mingetty is called, it reads a file called /etc/issue. There are a lot of existing variables you use. For example the prompt shown above in example is:

CentOS release 5 (Final)
Kernel \r on an \m

All of the available variables are list here on this page: http://www.lamp-tips.com/man-pages/mingetty/

If you were paying attention in the beginning of the post and looked at all of the available variables you can use, you would notice there is nothing in there which talks about IP. Since there is no variables available, you would have to sort of hack it. Put following in your /etc/rc.local file:

echo "CentOS release 5 (Final)" > /etc/issue
echo "Kernel \r on an \m" >> /etc/issue
echo `ifconfig eth0 | grep inet | cut -d : -f 2 | cut -d \ -f 1` >> /etc/issue

Getting an ip part can be modified to check another adapter such as eth1, eth2, etc. Or you can get it another way if you want. That all there is too. Reboot, and you should see your changes.

[correction 4.24.08] you do not have to reboot to see your changes.  Just press enter at the login prompt in console and it will re-read the issue file.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

Master1 server ip: 10.0.0.1
Master2 server ip: 10.0.0.2
Slave username: slaveuser
Slave pw: slavepw
Your data directory is: /usr/local/mysql/var/

Let us go through the steps you must take on Master1 to enable it to act as master and slave by using following configuration which goes under [mysqld] section:

# let's make it so auto increment columns behave by having different increments on both servers
auto_increment_increment=2
auto_increment_offset=1
# Replication Master Server
# binary logging is required for replication
log-bin=master1-bin
binlog-ignore-db=mysql
binlog-ignore-db=test
# required unique id between 1 and 2^32 - 1
server-id = 1
#following is the slave settings so this server can connect to master2
master-host = 10.0.0.2
master-user = slaveuser
master-password = slavepw
master-port = 3306

Following is the configuration which goes on master2 under [mysqld] section:

# let's make it so auto increment columns behave by having different increments on both servers
auto_increment_increment=2
auto_increment_offset=2
# Replication Master Server
# binary logging is required for replication
log-bin=master2-bin
binlog-ignore-db=mysql
binlog-ignore-db=test
# required unique id between 1 and 2^32 - 1
server-id = 2
#following is the slave settings so this server can connect to master2
master-host = 10.0.0.1
master-user = slaveuser
master-password = slavepw
master-port = 3306

On master1 server, go to mysql> prompt and add the appropriate user:

mysql> grant replication slave on *.* to slaveuser@'10.0.0.2' identified by 'slavepw';

On master2 server do the same but allow right ip:

mysql> grant replication slave on *.* to slaveuser@'10.0.0.1' identified by 'slavepw';

Restart both of the master servers and check slave status:

mysql> show slave status\G

That is all you have to do to set up the replication. Of course there are a lot more configuration options but this should get your replication going and you can tweak from here on.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

#!/bin/bash
db=$1
if [ "$db" = "" ]; then
echo "Usage: $0 db_name"
exit 1
fi
mkdir done
clear
for sql_file in *.sql; do
echo "Importing $sql_file";
mysql $db< $sql_file;
mv $sql_file done;
done

Related posts:

• How do I dump all tables in a database into separate files?
• MySQL backups using mysqldump

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

perl -w -i -p -e "s/search_text/replace_text/g" filename

-w turns warnings on
-i makes Perl operate on files in-place (if you would like to make backups, use -i.bak, this will save filename.bak files)
-p loops over the whole input
-e specifies Perl expression
filename works on one file at a time

Once we get the results we want, we can now pass it multiple files by doing something like:

perl -w -i -p -e "s/search_text/replace_text/g" *.php

This will search and replace within all php files in the directory you are in.

Now, let us say you want to go through your whole web directory and replace every place where you have “Perl is good” to “Perl is great”, you would use following command:

find /www_root -name "*.php"|xargs perl -w -i -p -e "s/Perl is good/perl is great/g"

find will start at /www_root, look for filenames which have .php extension, xargs takes that filename and passes it to perl as an arguement.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

yum -y install gmp-devel
wget http://freshmeat.net/redir/clamav/29355/url_tgz/clamav-0.91.2.tar.gz
adduser -M -s /bin/false clamav
tar zxf clamav-0.91.2.tar.gz
cd clamav-0.91.2
./configure --prefix=/usr/local/clamav
make install
for binaries in `find /usr/local/clamav/bin/*` ; do ln -s ${binaries} /usr/bin/; done

At this point Clam AntiVirus is installed and ready for use. Edit the configuration file and remove the line which says: Example It is there to ensure. If you want, you can look at other options but we don’t need to change anything else here to make ClamAV work for us.

vi /usr/local/clamav/etc/freshclam.conf #remove Example

Now let us run the freshclam which will download virus database and bring our virus database up to date. We should do this manually and make sure it didn’t give any errors. If this works, you will a lot of “downloading” messages.

/usr/bin/freshclam

If everything checks out, let us add this to our crontab to ensure our virus database is updated hourly. I chose to be updated every 9 minutes in to every hour. You can change to fit your needs or leave it as it is.

crontab -e

9 * * * * /usr/bin/freshclam –quiet

At this point our ClamAV virus database is up to date and now we can scan whichever directory we want. Go to the directory you want to scan and type:

clamscan -r -i

Once it is done scanning, it will display something similar to below.
-r parameter tells clamscan to recurse into directories
-i will print out infected filenames

----------- SCAN SUMMARY -----------
Known viruses: 159855
Engine version: 0.91.2
Scanned directories: 1437
Scanned files: 8836
Infected files: 0
Data scanned: 464.83 MB
Time: 103.678 sec (1 m 43 s)

Happy scanning!
————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

mkdir /backups/repos -p
for repostobackup in `ls /svn/` ; do
filename=`basename ${repostobackup}`
if [ ! $filename = "" ]; then
hot-backup.py --archive-type=bz2 /svn/${filename} /backups/repos
fi
done

This will create your backup files and compress them using bzip2. You can also use zip or gz if you prefer. Another thing you should do is to edit the hot-backup.py script and change num_backups to be whatever you think is a good number. I personally use: num_backups = 10

That’s all there is to it. Just add this script to your crons and your backups will be automated. You may want to consider moving your backups to another server by adding ftp, scp or rsync at the end of the script.

While I was looking around for solution for this problem on Google, I came upon few pages where they talked about if you have empty line before command, that command will not work. For example:

#this is a cron file

* * * * * /do/something

In this example, /do/something will not run since there is a blank line before it. You can fix this by moving that command up or put another comment above it. This is a very odd thing and I have never experienced it myself but I figured if you stumble upon this post looking for help, blank line before command in crontab might be your issue. Please comment if you had to delete a blank line to fix your crontab file. Also mention which OS you are using. To learn more about crond, see man crond and man crontab.

ssh_exchange_identification: Connection closed by remote host

After doing further research on the server I was trying to connect to (looking at logs) I noticed the server was denying connection based on ip.  I put my servers ip in /etc/hosts.allow and tried again.  This time I was connected without any problems.  Note that you do not have to restart SSH for hosts.allow change to take affect.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

On server1, you type: ssh-keygen -t rsa (just press enter to keep accepting defaults). You should see something like this:

ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
a2:b2:aw:w2:63:25:2a:62:fs:d5:ff:fd:11:f1:aa:60 root@server1

Fingerprint for your server will be different. Now cat /root/.ssh/id_rsa.pub Copy the contents it displays. You will need this for server2. Paste it into notepad or any other text editor and make sure it pastes as one line. This is very crucial you check this.

Now login to server2. Create the public key by typing: ssh-keygen -t rsa (this is same thing we did on server1). Once you are done, type vi /root/.ssh/authorized_keys2

Paste the content you copied earlier on server1. Make sure it is all on one line. Save/exit.  At this point, we should change the permissions on the file to make sure sshd likes it:  chmod 600 /root/.ssh/authorized_keys2

Go back to server1 and type ssh server2 You should be logged in with out having to put in a password. If you are prompted for password still, check server2 /root/.ssh/authorized_keys2 file and make sure everything you pasted is one line.

That is all you have to do set up public key authentication over ssh!

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

Let us dive into this. First we create user and set up directory structure.

echo "named:x:200:200:Nameserver:/chroot/named:/bin/false" >> /etc/passwd
echo "named:x:200:" >> /etc/group
mkdir -p /chroot/named
cd /chroot/named
mkdir -p dev etc/namedb/slave var/run
chown -R named:named /chroot/named/etc/namedb/slave
chown named:named /chroot/named/var/run
mknod /chroot/named/dev/null c 1 3
mknod /chroot/named/dev/random c 1 8
chmod 666 /chroot/named/dev/{null,random}
cp /etc/localtime /chroot/named/etc/

vi /etc/sysconfig/syslog
edit the line which starts with SYSLOGD_OPTIONS and edit it to look like: SYSLOGD_OPTIONS=”-m 0 -a /chroot/named/dev/log”
Let us restart syslog to use new settings and let us secure the physical files on the server.

/etc/rc.d/init.d/syslog stop
/etc/rc.d/init.d/syslog start
chown root /chroot
chmod 700 /chroot
chown named:named /chroot/named
chmod 700 /chroot/named
cd /chroot/named
chattr +i etc/localtime var

Let us clean up previous bind install since most linux installations have named (bind) pre-installed.

rpm -qa |grep bind
rpm -e --nodeps <copy-paste-all-the-packages-separated-by-space>

Let us get the source files for bind and install it. At time of writing, bind 9.4.1 is the latest.

wget http://ftp.isc.org/isc/bind9/9.4.1/bind-9.4.1.tar.gz
tar zxpfv bind-*.gz
cd bind*
./configure
make && make install

copy following content to /etc/init.d/named

#!/bin/sh
#
# named This shell script takes care of starting and stopping
# named (BIND DNS server).
#
# chkconfig: 345 55 45
# description: named (BIND) is a Domain Name Server (DNS) \
# that is used to resolve host names to IP addresses.
# probe: true
#
# Source function library.
. /etc/rc.d/init.d/functions
#
# Source networking configuration.
. /etc/sysconfig/network
#
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0
#
[ -f /usr/local/sbin/named ] || exit 0
[ -f /chroot/named/etc/named.conf ] || exit 0
#
# See how we were called.
case "$1" in
start)
# Start daemons.
echo -n "Starting named: "
daemon /usr/local/sbin/named -u named -t /chroot/named -c /etc/named.conf
echo
touch /var/lock/subsys/named
;;
stop)
# Stop daemons.
echo -n "Shutting down named: "
kill `pidof named`
echo
rm -f /var/lock/subsys/named
;;
status)
status named
exit $?
;;
restart)
$0 stop
$0 start
exit $?
;;
reload)
/usr/local/sbin/rndc reload
exit $?
;;
probe)
# named knows how to reload intelligently; we don't want linuxconf
# to offer to restart every time
/usr/local/sbin/rndc reload >/dev/null 2>&1 || echo start
exit 0
;;
#
*)
echo "Usage: named {start|stop|status|restart|reload}"
exit 1
esac
#
exit 0

Make it executable: chmod +x /etc/init.d/named
Let us set it so “named” will automatically start at boot up: chkconfig --add named

Save follow code into /chroot/named/etc/named.conf
options {
recursion no; // this will disable lookups against our server recursion no;
directory "/etc/namedb"; // Working directory
pid-file "/var/run/named.pid"; // Put pid file in working dir
forwarders {
10.10.10.10; //ip of dns server to forward requests to
};
statistics-file "/var/run/named.stats";
query-source address * port 53;
version "Bind 10";
};
controls {
inet 127.0.0.1 port 953
allow { 127.0.0.1; } keys { "rndc-key"; };
};
// Root server hints
zone "." {
type hint;
file "root.hint";
};
// Provide a reverse mapping for the loopback address 127.0.0.1
zone "0.0.127.in-addr.arpa" {
type master;
file "db.127.0.0";
notify no;
};

Save following in /chroot/named/etc/namedb/root.hint

; This file holds the information on root name servers needed to
; initialize cache of Internet domain name servers
; (e.g. reference this file in the "cache . <file>"
; configuration file of BIND domain name servers).
;
; This file is made available by InterNIC
; under anonymous FTP as
; file /domain/named.root
; on server FTP.INTERNIC.NET
;
; last update: Nov 5, 2002
; related version of root zone: 2002110501
;
;
; formerly NS.INTERNIC.NET
;
. 3600000 IN NS A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4
;
; formerly NS1.ISI.EDU
;
. 3600000 NS B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET. 3600000 A 128.9.0.107
;
; formerly C.PSI.NET
;
. 3600000 NS C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12
;
; formerly TERP.UMD.EDU
;
. 3600000 NS D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90
;
; formerly NS.NASA.GOV
;
. 3600000 NS E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10
;
; formerly NS.ISC.ORG
;
. 3600000 NS F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241
;
; formerly NS.NIC.DDN.MIL
;
. 3600000 NS G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
;
. 3600000 NS H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53
;
; formerly NIC.NORDU.NET
;
. 3600000 NS I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17
;
; operated by VeriSign, Inc.
;
. 3600000 NS J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET. 3600000 A 192.58.128.30
;
; housed in LINX, operated by RIPE NCC
;
. 3600000 NS K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET. 3600000 A 193.0.14.129
;
; operated by IANA
;
. 3600000 NS L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
;
; housed in Japan, operated by WIDE
;
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33
; End of File

This should get you started. Now just create appropriate zone files and you are good to go.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

# dmesg | grep RAMDISK
RAMDISK driver initialized: 16 RAM disks of 16384K size 1024 blocksize

You should get above output on CentOS and RHEL.  Other linux flavors will have similar output as well.  If you would like to see how they are named and what you would need to refer to, do the following:

# ls -l /dev/ram*
lrwxrwxrwx 1 root root 4 Apr 24 12:05 /dev/ram -> ram1
brw-rw---- 1 root disk 1, 0 Apr 24 12:05 /dev/ram0
brw-rw---- 1 root disk 1, 1 Apr 24 12:05 /dev/ram1
brw-rw---- 1 root disk 1, 10 Apr 24 12:05 /dev/ram10
brw-rw---- 1 root disk 1, 11 Apr 24 12:05 /dev/ram11
brw-rw---- 1 root disk 1, 12 Apr 24 12:05 /dev/ram12
brw-rw---- 1 root disk 1, 13 Apr 24 12:05 /dev/ram13
brw-rw---- 1 root disk 1, 14 Apr 24 12:05 /dev/ram14
brw-rw---- 1 root disk 1, 15 Apr 24 12:05 /dev/ram15
brw-rw---- 1 root disk 1, 2 Apr 24 12:05 /dev/ram2
brw-rw---- 1 root disk 1, 3 Apr 24 12:05 /dev/ram3
brw-rw---- 1 root disk 1, 4 Apr 24 12:05 /dev/ram4
brw-rw---- 1 root disk 1, 5 Apr 24 12:05 /dev/ram5
brw-rw---- 1 root disk 1, 6 Apr 24 12:05 /dev/ram6
brw-rw---- 1 root disk 1, 7 Apr 24 12:05 /dev/ram7
brw-rw---- 1 root disk 1, 8 Apr 24 12:05 /dev/ram8
brw-rw---- 1 root disk 1, 9 Apr 24 12:05 /dev/ram9
lrwxrwxrwx 1 root root 4 Apr 24 12:05 /dev/ramdisk -> ram0

All those ramdisks listed have same size.  In above example, they are all 16MB.  Let us change that so we have more space allowed.  Note that I say allowed and not allocated.  We allocate space in one of the later steps by formatting one of the drives above.   Let us set it up so we have 128 MB.  Since this has to be in multiples of 1024, we will setup Ramdisk to have 131072K. 

vi /etc/grub.conf

Find first line which looks similar to following:

kernel /vmlinuz-2.6.9-42.0.10.EL ro root=/dev/VolGroup00/LogVol00

add ramdisk_size=131072 to the end of the line.  Now your line should look like:

kernel /vmlinuz-2.6.9-42.0.10.EL ro root=/dev/VolGroup00/LogVol00 ramdisk_size=131072 Save and exit grub.conf.  At this point you have it configured to have ramdisk with new size but it does not take effect until you reboot your system.  Once you have rebooted your system, we can start doing rest of configurations.

mke2fs -m 0 /dev/ram0

This will format the ram0 ramdrive for us to use. At this point, kernel will allocate space for you.  Let us setup Ramdisk mount point so we can use it.  We will also have it be owned by user “sunny” so that user can read/write to that mount.

mkdir /home/ramdisk
mount /dev/ram0 /home/ramdisk
chown sunny.sunny /home/ramdisk

At this point you should be able to type:  mount and see your new Ramdisk drive mounted on /home/ramdisk

Remember that everything you put on this drive will be gone if you reboot your server.  If you unmounted the Ramdisk drive and remounted it, your files will still be there.  It is because your system has that much ram set aside for your Ramdisk and will not use it for anything else.   If you would like to setup Ramdisk the same next time you boot up, add these lines to your /etc/rc.local files.

mke2fs -m 0 /dev/ram0
mount /dev/ram0 /home/ramdisk
chown sunny.sunny /home/ramdisk

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

YUM Install 

Easiest way to install subversion is via “yum” by typing:

yum install subversion

Once install is done, confirm it by typing “svn” at the prompt and you should get:

Type 'svn help' for usage.

At this point you can skip to “Setting up Subversion repository” part.

SOURCE Install

Obtain source from:  Subversion.  At the time of writing, latest (1.4.3) version can be obtain from this link:  http://subversion.tigris.org/downloads/subversion-1.4.3.tar.gz

tar zxf subversion*
cd subversion*
./configure
make && make install

after everything goes well, type svn at the prompt and you should get:

Type 'svn help' for usage.

Setting up Subversion repository

adduser svnusers
mkdir repos/branches -p
mkdir repos/trunk -p
mkdir repos/tags -p
mkdir /svn
svnadmin create /svn/demorepo
svn import --message "Initial set up" repos file:///svn/demorepo
cd /svn/demorepo
chown .svnusers . -R
chmod 775 * -R
chmod +s db

Thats all there is to it to setup Subversion repository.  At this point, you should add any users you want to have access to the repository by adding them to “svnusers” group.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

#!/bin/sh
#
# Created by: Sunny Walia
# Date created: 5/24/03
# Date Modified: 5/29/07
# Purpose: do any type of preprocessing before log.php can do its work.
# Also does log rotation and backup.
#
# Modification history:
# 5/25/03: added comments.
# Gzip and move to backup logs folder
# added config info on top
#
#
# configuration info
SERVERNAME="svr1"
WORKINGDIR="/admin/backups/$SERVERNAME/logs/"
BACKUPLOGSDIR="/admin/backups/$SERVERNAME/logs/archived/"
BACKUP_DIR="/admin/backups/$SERVERNAME/"
LOGDIR="/usr/local/apache2/logs/"
DATE=`date +%m%d%y%H`
APACHCTL_LOC="/usr/local/apache2/bin/"
#
mkdir $WORKINGDIR -p
mkdir $BACKUPLOGSDIR -p
mkdir $BACKUP_DIR -p
#
# move the logs into their temp name so apache can continue to write to it
mv ${LOGDIR}access_log ${LOGDIR}${SERVERNAME}_access_log.old
mv ${LOGDIR}error_log ${LOGDIR}${SERVERNAME}_error_log.old
#
# restart apache gracefully so it will finish what its doing and start a new log file
# when done serving current requests
${APACHCTL_LOC}apachectl graceful
#
# give some time to apache to finish serving pending requests (in secs)
sleep 15
#
# copy the files to our directory for processing
cp ${LOGDIR}${SERVERNAME}_access_log.old ${WORKINGDIR}${SERVERNAME}_access_log
cp ${LOGDIR}${SERVERNAME}_error_log.old ${WORKINGDIR}${SERVERNAME}_error_log
#
mv ${LOGDIR}${SERVERNAME}_access_log.old ${LOGDIR}${SERVERNAME}_access_log.$DATE
mv ${LOGDIR}${SERVERNAME}_error_log.old ${LOGDIR}${SERVERNAME}_error_log.$DATE
gzip ${LOGDIR}${SERVERNAME}_access_log.$DATE
gzip ${LOGDIR}${SERVERNAME}_error_log.$DATE
#
# we move instead of copy than delete since if mv fails, we still have originals
# mv can fail if target location is full
mv ${LOGDIR}${SERVERNAME}_access_log.$DATE.gz $BACKUPLOGSDIR
mv ${LOGDIR}${SERVERNAME}_error_log.$DATE.gz $BACKUPLOGSDIR


Let us make the script executable:
chmod +x script_name.sh

You can automate this to happen every day by putting it in your crontab:
crontab -e

1 0 * * * /path/to/this/script

This will rotate your logs at 12:01 AM every day.

————————————-
DISCLAIMER: Please be smart and use code found on internet carefully. Make backups often. And yeah.. last but not least.. I am not responsible for any damage caused by this posting. Use at your own risk.

rsync -ae ssh server1:/home /home/backups/server1_home_backup/

This command will download all the files/directories from /home on server1 and copies them to /home/backups/server1_home_backup/
-a = archive mode. This will preserve permissions, timestamps, etc.
-e = specify which remote shell to use. In our case, we want to use ssh which follow right after “e”

Let us improve on this and add couple more parameters:

rsync -zave ssh --progress server1:/home /home/backups/server1_home_backup/
-z = adds zip compression.
-v = verbose
–progress = my favorite parameter when I am doing rsync manually, not so good when you have it in cron. This show progress (how_many_files_left/how_many_files_total) and speed along with some other useful data.

Great.. we are moving along pretty good. Let us add some security to make sure things work the way we want to.

rsync --delete-after -zave ssh --progress server1:/home /home/backups/server1_home_backup/

–delete-after = this will delete files on backup server which are missing from source after ALL syncing is done. If you don’t care of having extra files on your backup server and have plenty of disk space to spare, do not use this parameter.

Lastly, one of the VERY handy parameters,

rsync --delete-after -zave ssh --progress server1:/home /home/backups/server1_home_backup/ -n

The -n (or –dry-run) parameter is great to use for testing. It will not transfer or delete any files, rather will report to you what it would have done if it was ran with out -n parameter. This way you can test it with out destroying or transfering data just to find out that is not what you wanted.

For further reading: man rsync

NOTE: This set up is very “open” and should not be used on servers which are facing the world. This is for private network where you trust all the computers and its users.

Installing Samba (using yum on CentOS and Fedora): yum install samba
Installing Samba (using rpm):

1. Obtain Samba rpm from rhn.redhat.com
2. rpm -ivh samba*.rpm

Configuring Samba:
cd /etc/samba
mv smb.conf smb.conf.backup
vi smb.conf

Paste content below in to your vi:

[global]
workgroup = wrkgrp
netbios name = smbserver
security = SHARE
load printers = No
default service = global
path = /home
available = No
encrypt passwords = yes
[share]
writeable = yes
admin users = smbuser
path = /home/share
force user = root
valid users = smbuser
public = yes
available = yes

save and exit

adduser smbuser #add unix account
passwd smbuser #set unix account password
smbpasswd -a smbuser #lets create same user account on samba
<put same password as your unix account password>
/etc/init.d/smb restart

Now let us setup drive letter on our Windows so we can easily access these files.

Start -> run -> cmd <enter>

At the prompt type: net use z: \\ip_of_your_samba_server\share /user: smbuser password_you_assigned

That is it! At this point you have successfully set up Samba under Linux and are now successfully connected to your share from your Windows machine.

You can test to see if you have LWP installed by typing:
perl -MLWP -le "print(LWP->VERSION)"
If you get something like: Can’t locate LWP.pm in @INC means that you don’t have it installed. To install LWP, type:
perl -MCPAN -eshell
NOTE: most times it is okey for you to accept default answers to questions cpan asks.
You can read through cpan help by typing “h” without the quotes at cpan> prompt.
To continue installing LWP, type:
install Bundle::LWP
After few questions, and some text scrolling, you will have LWP installed. If for some reason you don’t want to do it this way, you can always obtain source for the module you are trying to install and build it from source files. You can obtain these files from CPAN site

10.0.0.2:/export/files /files intr

After that I tested the setting by typing: mount /files Everything worked as expected and files was mounted successfully. At this point I wanted to make sure server will do nfs mounts automatically at boot up. To my surprise once I rebooted the server, nfs mount did not happen. I checked the logs and found this:

May 11 11:00:24 www3 mount: mount: mount to NFS server '10.0.0.2' failed:
May 11 11:00:24 www3 mount: System Error: No route to host.

But once server booted up, I typed mount /files and again, mount worked great. After poking around for a while I found out that when netfs script runs, netfs can not find network routes (due to network is still initializing). I tried few ways to get around this issue and settled on following solution:

vi /etc/init.d/netfs
insert: action $”Sleeping for 30 secs: ” sleep 30
right after: [ ! -f /var/lock/subsys/portmap ] && service portmap start
and right before: action $”Mounting NFS filesystems: ” mount -a -t nfs,nfs4

Basically we are going to give enough time for network to start and set up routes etc. You can play with that number after sleep command (we are basically pausing netfs script execution for 30 secs) and see what works for you. Once you are done, save/exit and reboot the server to see if number you used is sufficient sleep time. You can type df -h to see if it was mounted. If it wasn’t mounted, you can check /var/log/messages to see if nic was starting after nfs mount. If it is after, you will have to increase that number after sleep. Remember that you are only pausing the netfs script execution. Rest of the system continues to boot up. After I made changes, I checked my df output after reboot and my mount was there. I also checked /var/log/messages to see if everything looks ok there:

May 11 11:22:14 www3 kernel: bnx2: eth0 NIC Link is Up, 1000 Mbps full duplex
May 11 11:22:16 www3 netfs: Sleeping for 30 secs: succeeded
May 11 11:22:17 www3 netfs: Mounting NFS filesystems: succeeded

for old in *.php3; do cp $old `basename $old .php3`.php; done

Thats all there is to it. Let us say you need to rename index.php3 to index.php. The way above snippet works is that it loops through current directory and finds all the files with extension “.php3″ and processes ‘em one by one. In our index.php3 file example, it finds index.php3 file, does a cp index.php3 `basename index.php3 .php3`.php <- basename returns “index” so you add .php to it and now you are left with index.php. Of course you can do mv command if you want to just move the file to new name. I would suggest doing cp first to make sure things work the way you want ‘em to.