fengcool.com » Linux

cp file always getting overwrite prompt?

rick — Thu, 26 Nov 2009 05:32:09 +0000

wondering why always getting overwrite prompt when use “cp” command with “-f” option

try this,

1. login as root

1	vi /root/.bashrc

2. comment out this line

1	#alias cp='cp -i'

3. logout and login again

Rsync server and client – backup your server files

rick — Thu, 30 Jul 2009 17:28:53 +0000

rsync can synchronizes files and directories from one server to another. It’s perfectly for backup or create a mirror site purpose.

This tutorial shows you step by step to create a rsync server and client server.

First of all, you must have rsync installed. For fedora, rsync should be included by default. If you don’t have it, run

1	yum install rsync

Setup rsync server

Create rsync configuration file:

cd /etc
mkdir rsyncd
cd rsyncd
touch rsyncd.conf
touch rsyncd.motd
touch rsyncd.user
chmod 600 rsyncd.user

edit rsyncd.user file:
vi /etc/rsyncd.user

1	my_rsync_user_1:user_1_password

edit rsyncd.conf file:

pid file=/var/run/rsyncd.pid
port=873
uid=root
gid=root
use chroot=yes
read only=yes
 
# limit access to LANS
hosts allow=192.168.2.0/255.255.255.0   #default, listen to lan server
host deny=*
 
max connections=5
motd file=/etc/rsyncd/rsyncd.motd
 
log format=%t%a%m%f%b
syslog facility=local3
timeout=300
 
[profile_1]          #profile name
path = /path/to/backup/directory
ignore errors
read only = false
list = false
hosts allow = 66.66.66.66   #listen to client server which use public ip
hosts deny = 0.0.0.0/32
auth users = my_rsync_user_1
secrets file = /etc/rsyncd/rsyncd.user
 
#[profile_1]          #another profile name
#path = /path/to/backup/directory/2
#ignore errors
#read only = false
#list = false
#hosts allow = 88.88.88.88   #listen to client server which use public ip
#hosts deny = 0.0.0.0/32
#auth users = my_rsync_user_2
#secrets file = /etc/rsyncd/rsyncd.user

Next, create init start up script
vi /etc/init.d/rsyncd

#!/bin/sh
#
# Startup script for rsyncd daemon
#
# chkconfig: 35 90 10
# description: Server data for sync to other server
# processname rsync
 
# Source function library
. /etc/rc.d/init.d/functions
 
prog=rsync
conf=/etc/rsyncd/rsyncd.conf
 
case "$1" in
    start)
        echo -n "Starting rsync daemon: "
        daemon /usr/bin/$prog --daemon --config=$conf
        RETVAL=$?
        echo
        [ $RETVAL = 0 ] && touch /var/lock/subsys/$prog
        ;;
    stop)
        echo -n "Shutting down $prog: "
        killproc -d 60 $prog
        RETVAL=$?
        echo
        [ $RETVAL = 0 ] && rm -f /var/lock/subsys/$prog
        ;;
    status)
        status $prog
        ;;
    restart)
        $0 stop
        $0 start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart|status}"
        exit 1
esac
 
exit 0

make /etc/init.d/rsyncd executable, and register this service

3
4
5

chmod +x /etc/init.d/rsyncd 
/sbin/chkconfig --add rsyncd
/sbin/service rsyncd start

Setup rsync client

first, of course you must have rsync installed on client server

make rsync password file

cd /etc
mkdir rsync
cd rsync
touch rsync.pwd
chmod 600 rsync.pwd

vi /etc/rsync/rsync.pwd

1	user_1_password

execute this command to start synchronize file to server

1	rsync -vrtLogp --progress /path/to/directory/to/be/backup/* my_rsync_user_1@[SERVER_IP]::profile_1 --password-file=/etc/rsync/rsync.pwd

where [SERVER_IP] is rsync server IP

Plesk common shell commands

Nelson — Mon, 08 Jun 2009 18:02:40 +0000

Reload vhost.conf for single domain

1	/usr/local/psa/admin/sbin/websrvmng --reconfigure-vhost --vhost-name=

Update AWStats for only 1 domain in Plesk

1	/usr/local/psa/admin/sbin/statistics --calculate-one --domain-name=you-domain.com

Backup newly modified files

rick — Mon, 02 Feb 2009 03:27:03 +0000

My server backups over 20GB files everyday. It takes hours to tar those huge amount of files. I think this kind of stupid task is harmful to hard driver. One more stupid issue is that over 99% of files are not modified since last backup. So, here is the command to let me backup newly modified files only.

tar -zcvf /save/to/file.tar /filePath/* –newer-mtime ‘1 days ago’

You may want to change “1 days ago” to 2 days, or 5 days.

By the way, it’s better to do full backup monthly or bi-monthly.

Linux – delete files which modified time older than 7 days

rick — Mon, 02 Feb 2009 03:13:24 +0000

find /filePath/* -mtime +7 -delete

find /filePath/* -mtime +7 -exec rm {} \;

Where “-mtime” parameter will look for file modified time older than “+7″ days. You may want to change “+7″ to longer days, for example “+30″ days, “+90″ days

“-exec” parameter allows you to call another command. The “{} \;” is required at the end.

ffmpeg – capture screenshot from a video file

rick — Sat, 13 Dec 2008 02:53:58 +0000

1	ffmpeg -i /my_video_file_dir/video.flv -y -f image2 -ss 8 -sameq -t 0.001 -s 320*240 /image_dir/screenshot.jpg

320*240 : image dimension is 320 pixels width and 240 pixels height
-ss 8 : screenshot will be taken at 8 second after video starts.

Linux ffmpeg audio conversion – MP3 to FLV

rick — Fri, 05 Dec 2008 04:18:59 +0000

Want to play MP3 files on your website? The best and most common way is using flash video file which compress audio and video better for internet use like YouTube. Here is the instruction I used ffmpeg to convert MP3 to FLV file.

ffmpeg – a program that allow convert audio in numerous formats.

Installing ffmpeg
edit / etc/yum.repos.d/CentOS-Base.repo , add following lines at the end of file

[dag]
name=Dag RPM Repository for Centos
baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
enabled=1

run this command

1	yum install ffmpeg

Convert MP3 to FLV

1	ffmpeg -y -i /home/song.mp3 -f flv -acodec mp3 -ab 64 -ac 1 /home/song.flv

Simple helloworld c++ program to test noexec tmp partition

Nelson — Wed, 03 Dec 2008 16:46:28 +0000

#include 
 
int main()
{
  std::cout << "Hello world, compiled with g++ on linux" << std::endl;
  return 0;
}

compile this and move to your secured tmp partition and execute it. If you get a permission error, tmp partition is mounted correctly with noexec.

Synchronize linux date and time using ntpdate

rick — Mon, 01 Dec 2008 17:15:13 +0000

ntpdate synchronize and set computers’ date and time via Network Time Protocol (NTP) server(s).

1	/usr/sbin/ntpdate -u 0.fedora.pool.ntp.org

0.fedora.pool.ntp.org is NTP server. If this server is not working, find another one.

Download all file recursively from ftp server

rick — Sun, 30 Nov 2008 20:52:27 +0000

ncftpget is able to let you download entire ftp directory and sub directories from remote ftp server.

Install ncftp client

1	yum install ncftp

Start downloading

1	ncftpget -R -v -u "username" -p "userpassword" ftp.someserver.com /home/save_at_here /downloads

where,

-R : download all subdirectories and files (recusive)
-v : verbose, show download activity
-u : ftp server user name
-p : ftp server user login (if skipped, will prompt to ask password)
ftp.someserver.com : ftp server domain or IP
/home/save_at_here : all downloaded file will save in this directory
/downloads : remote ftp server directory you wish to copy