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Rsync (Remote Sync) is a most commonly used command for copying and synchronizingfiles and directories remotely as well as locally in Linux/Unix systems. With the help ofrsync command you can copy and synchronize your data remotely and locally across directories, across disks and networks, perform data backups and mirroring between two Linux machines.

Rsync Local and Remote File Synchronization

This article explains 10 basic and advanced usage of the rsync command to transfer your files remotely and locally in Linux based machines. You don’t need to be root user to runrsync command.

Some advantages and features of Rsync command

It efficiently copies and sync files to or from a remote system.
Supports copying links, devices, owners, groups and permissions.
It’s faster than scp (Secure Copy) because rsync uses remote-update protocol which allows to transfer just the differences between two sets of files. First time, it copies the whole content of a file or a directory from source to destination but from next time, it copies only the changed blocks and bytes to the destination.
Rsync consumes less bandwidth as it uses compression and decompression method while sending and receiving data both ends.

Basic syntax of rsync command

# rsync options source destination

Some common options used with rsync commands

-v : verbose
-r : copies data recursively (but don’t preserve timestamps and permission while transferring data
-a : archive mode, archive mode allows copying files recursively and it also preserves symbolic links, file permissions, user & group ownerships and timestamps
-z : compress file data
-h : human-readable, output numbers in a human-readable format

Install rsync in your Linux machine

We can install rsync package with the help of following command.

# yum install rsync (On Red Hat based systems)
# apt-get install rsync (On Debian based systems)

1. Copy/Sync Files and Directory Locally

Copy/Sync a File on a Local Computer

This following command will sync a single file on a local machine from one location to another location. Here in this example, a file name backup.tar needs to be copied or synced to/tmp/backups/ folder.

[root@tecmint]# rsync -zvh backup.tar /tmp/backups/

created directory /tmp/backups

backup.tar

sent 14.71M bytes  received 31 bytes  3.27M bytes/sec

total size is 16.18M  speedup is 1.10

In above example, you can see that if the destination is not already exists rsync will create a directory automatically for destination.

Copy/Sync a Directory on Local Computer

The following command will transfer or sync all the files of from one directory to a different directory in the same machine. Here in this example, /root/rpmpkgs contains some rpm package files and you want that directory to be copied inside /tmp/backups/ folder.

[root@tecmint]# rsync -avzh /root/rpmpkgs /tmp/backups/

sending incremental file list

rpmpkgs/

rpmpkgs/httpd-2.2.3-82.el5.centos.i386.rpm

rpmpkgs/mod_ssl-2.2.3-82.el5.centos.i386.rpm

rpmpkgs/nagios-3.5.0.tar.gz

rpmpkgs/nagios-plugins-1.4.16.tar.gz

sent 4.99M bytes  received 92 bytes  3.33M bytes/sec

total size is 4.99M  speedup is 1.00

2. Copy/Sync Files and Directory to or From a Server

Copy a Directory from Local Server to a Remote Server

This command will sync a directory from a local machine to a remote machine. For example: There is a folder in your local computer “rpmpkgs” which contains some RPM packages and you want that local directory’s content send to a remote server, you can use following command.

[root@tecmint]$ rsync -avz rpmpkgs/ root@192.168.0.101:/home/

root@192.168.0.101's password:

sending incremental file list

./

httpd-2.2.3-82.el5.centos.i386.rpm

mod_ssl-2.2.3-82.el5.centos.i386.rpm

nagios-3.5.0.tar.gz

nagios-plugins-1.4.16.tar.gz

sent 4993369 bytes  received 91 bytes  399476.80 bytes/sec

total size is 4991313  speedup is 1.00

Copy/Sync a Remote Directory to a Local Machine

This command will help you sync a remote directory to a local directory. Here in this example, a directory /home/tarunika/rpmpkgs which is on a remote server is being copied in your local computer in /tmp/myrpms.

[root@tecmint]# rsync -avzh root@192.168.0.100:/home/tarunika/rpmpkgs /tmp/myrpms

root@192.168.0.100's password:

receiving incremental file list

created directory /tmp/myrpms

rpmpkgs/

rpmpkgs/httpd-2.2.3-82.el5.centos.i386.rpm

rpmpkgs/mod_ssl-2.2.3-82.el5.centos.i386.rpm

rpmpkgs/nagios-3.5.0.tar.gz

rpmpkgs/nagios-plugins-1.4.16.tar.gz

sent 91 bytes  received 4.99M bytes  322.16K bytes/sec

total size is 4.99M  speedup is 1.00

3. Rsync Over SSH

With rsync, we can use SSH (Secure Shell) for data transfer, using SSH protocol while transferring our data you can be ensured that your data is being transferred in a secured connection with encryption so that nobody can read your data while it is being transferred over the wire on the internet.

Also when we use rsync we need to provide the user/root password to accomplish that particular task, so using SSH option will send your logins in an encrypted manner so that yourpassword will be safe.

Copy a File from a Remote Server to a Local Server with SSH

To specify a protocol with rsync you need to give “-e” option with protocol name you want to use. Here in this example, We will be using “ssh” with “-e” option and perform data transfer.

[root@tecmint]# rsync -avzhe ssh root@192.168.0.100:/root/install.log /tmp/

root@192.168.0.100's password:

receiving incremental file list

install.log

sent 30 bytes  received 8.12K bytes  1.48K bytes/sec

total size is 30.74K  speedup is 3.77

Copy a File from a Local Server to a Remote Server with SSH

[root@tecmint]# rsync -avzhe ssh backup.tar root@192.168.0.100:/backups/

root@192.168.0.100's password:

sending incremental file list

backup.tar

sent 14.71M bytes  received 31 bytes  1.28M bytes/sec

total size is 16.18M  speedup is 1.10

4. Show Progress While Transferring Data with rsync

To show the progress while transferring the data from one machine to a different machine, we can use ‘–progress’ option for it. It displays the files and the time remaining to complete the transfer.

[root@tecmint]# rsync -avzhe ssh --progress /home/rpmpkgs root@192.168.0.100:/root/rpmpkgs

root@192.168.0.100's password:

sending incremental file list

created directory /root/rpmpkgs

rpmpkgs/

rpmpkgs/httpd-2.2.3-82.el5.centos.i386.rpm

           1.02M 100%        2.72MB/s        0:00:00 (xfer#1, to-check=3/5)

rpmpkgs/mod_ssl-2.2.3-82.el5.centos.i386.rpm

          99.04K 100%  241.19kB/s        0:00:00 (xfer#2, to-check=2/5)

rpmpkgs/nagios-3.5.0.tar.gz

           1.79M 100%        1.56MB/s        0:00:01 (xfer#3, to-check=1/5)

rpmpkgs/nagios-plugins-1.4.16.tar.gz

           2.09M 100%        1.47MB/s        0:00:01 (xfer#4, to-check=0/5)

sent 4.99M bytes  received 92 bytes  475.56K bytes/sec

total size is 4.99M  speedup is 1.00

5. Use of –include and –exclude Options

These two options allows us to include and exclude files by specifying parameters with these option helps us to specify those files or directories which you want to include in your sync and exclude files and folders with you don’t want to be transferred.

Here in this example, rsync command will include those files and directory only which starts with ‘R’ and exclude all other files and directory.

[root@tecmint]# rsync -avze ssh --include 'R*' --exclude '*' root@192.168.0.101:/var/lib/rpm/ /root/rpm

root@192.168.0.101's password:

receiving incremental file list

created directory /root/rpm

./

Requirename

Requireversion

sent 67 bytes  received 167289 bytes  7438.04 bytes/sec

total size is 434176  speedup is 2.59

6. Use of –delete Option

If a file or directory not exist at the source, but already exists at the destination, you might want to delete that existing file/directory at the target while syncing .

We can use ‘–delete‘ option to delete files that are not there in source directory.

Source and target are in sync. Now creating new file test.txt at the target.

[root@tecmint]# touch test.txt
[root@tecmint]# rsync -avz --delete root@192.168.0.100:/var/lib/rpm/ .
Password:
receiving file list ... done
deleting test.txt
./
sent 26 bytes  received 390 bytes  48.94 bytes/sec
total size is 45305958  speedup is 108908.55

Target has the new file called test.txt, when synchronize with the source with ‘–delete‘ option, it removed the file test.txt.

7. Set the Max Size of Files to be Transferred

You can specify the Max file size to be transferred or sync. You can do it with “–max-size” option. Here in this example, Max file size is 200k, so this command will transfer only those files which are equal or smaller than 200k.

[root@tecmint]# rsync -avzhe ssh --max-size='200k' /var/lib/rpm/ root@192.168.0.100:/root/tmprpm

root@192.168.0.100's password:

sending incremental file list

created directory /root/tmprpm

./

Conflictname

Group

Installtid

Name

Provideversion

Pubkeys

Requireversion

Sha1header

Sigmd5

Triggername

__db.001

sent 189.79K bytes  received 224 bytes  13.10K bytes/sec

total size is 38.08M  speedup is 200.43

8. Automatically Delete source Files after successful Transfer

Now, suppose you have a main web server and a data backup server, you created a daily backup and synced it with your backup server, now you don’t want to keep that local copy of backup in your web server.

So, will you wait for transfer to complete and then delete those local backup file manually? Of Course NO. This automatic deletion can be done using ‘–remove-source-files‘ option.

[root@tecmint]# rsync --remove-source-files -zvh backup.tar /tmp/backups/

backup.tar

sent 14.71M bytes  received 31 bytes  4.20M bytes/sec

total size is 16.18M  speedup is 1.10

[root@tecmint]# ll backup.tar

ls: backup.tar: No such file or directory

9. Do a Dry Run with rsync

If you are a newbie and using rsync and don’t know what exactly your command going do. Rsync could really mess up the things in your destination folder and then doing an undo can be a tedious job.

Use of this option will not make any changes only do a dry run of the command and shows the output of the command, if the output shows exactly same you want to do then you can remove ‘–dry-run‘ option from your command and run on the terminal.

root@tecmint]# rsync --dry-run --remove-source-files -zvh backup.tar /tmp/backups/

backup.tar

sent 35 bytes  received 15 bytes  100.00 bytes/sec

total size is 16.18M  speedup is 323584.00 (DRY RUN)

10. Set Bandwidth Limit and Transfer File

You can set the bandwidth limit while transferring data from one machine to another machine with the the help of ‘–bwlimit‘ option. This options helps us to limit I/O bandwidth.

[root@tecmint]# rsync --bwlimit=100 -avzhe ssh  /var/lib/rpm/  root@192.168.0.100:/root/tmprpm/
root@192.168.0.100's password:
sending incremental file list
sent 324 bytes  received 12 bytes  61.09 bytes/sec
total size is 38.08M  speedup is 113347.05

Also, by default rsync syncs changed blocks and bytes only, if you want explicitly want to sync whole file then you use ‘-W‘ option with it.

[root@tecmint]# rsync -zvhW backup.tar /tmp/backups/backup.tar
backup.tar
sent 14.71M bytes  received 31 bytes  3.27M bytes/sec
total size is 16.18M  speedup is 1.10

That’s all with rsync now, you can see man pages for more options. Stay connected withTecmint for more exciting and interesting tutorials in future. Do leave your comments andsuggestions.

Netstat is used to display network connections, routing tables and a whole bunch of network and interface stats.

· lsof on the other hand is used to list out open files. So, if you want to find out what all files are currently open just run lsof. And since in Linux "Everything is a File", we can use lsof to print network connections too.

Lets start learning by resolving common queries.

How to display a list of open ports?

This can be done using both netstat and lsof.

[shredder12]$ netstat -n -A inet

-n is used to display numeric addresses instead of trying to determine symbolic hostnames

-A is used to define the address family we are concerned with. Here its internet connections on IPv4 network, so inet(user inet6 for IPv6 connections).

[shredder12]$ lsof -i

How to display a list of Active connections?

In case you noticed the output of the command mentioned above, they actually show the active connections.

[shredder12]$ netstat -n -A inet

[shredder12]$ lsof -i

How to display a list of listening ports?

Use the --listen flag with netstat to get a list.

[shredder12]$ netstat --listen -A inet

How to display a list of active TCP or UDP connections?

With netstat, we can use the flag -t to denote TCP connections only.

[shredder12]$ netstat -n -A inet -t

similarly, -u for UDP connections.

The -i flag of lsof provides a lot of configurable options. Use the following command to filter out TCP connections.

[shredder12]$ lsof -i4TCP

Please note no space between i4 and TCP. This means TCP connections on IPv4 network. Similary one can use i6 for IPv6 and UDP for udp connections.

How to find out all the ports being used by a single application or process using PID?

With netstat option -p you can even list out the program a port/socket is associated with. So, lets run -p with our active connections command and grep the pid.

[shredder12]$ netstat -A inet -n -p | grep 1413

You can find out the PID of a process using ps or pgrep.

[shredder12]$ ps -e | grep firefox

[shredder12]$ pgrep firefox

How to find out all the files being used by a program or application using PID?

Since we are concerned with files, lsof comes into play here. Here the -p option used along with the PID to catch the files associated with that process.

[shredder12]$ lsof -i4TCP -a -p 1413

The -a flag is used to tell lsof to AND the result of all the options used.

Wednesday, October 1, 2014

Thursday, September 4, 2014

https://www.linode.com/docs/networking/linux-static-ip-configuration

Saturday, July 26, 2014

Sunday, March 2, 2014

Wednesday, February 26, 2014

Thursday, February 6, 2014