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Tag: Commands

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VBScript that read from one file to write in another

Hello,

Here I leave you a VBScript I did to modify a TXT file with the information of other file.

We read the file “C:\myfolder\information.txt” and fil the variables.
We read and write the file “C:\myfolder\final.txt” with the values we did
read before in the case is needed.

‘***************************************************************************
***********
Const ForReading=1
Const ForWriting=2
Set objFSO = CreateObject(“Scripting.FileSystemObject”)
folder = “C:\myfolder\”
filePath = folder & “final.txt”
filePathinf = folder & “information.txt”
Set myFile = objFSO.OpenTextFile(filePath, ForReading, True)
Set myFileinf = objFSO.OpenTextFile(filePathinf, ForReading, True)
Set myTemp= objFSO.OpenTextFile(filePath & “.tmp”, ForWriting, True)

mypo = “12345678”
mypocheck = false

commonname = “name”
sname = “sname”
myplu = “123”

dim mygs1_128(400)
dim mypeso(400)
index = 1

Do While Not myFileinf.AtEndofStream
myLineinf = myFileinf.ReadLine

if InStr(myLineinf, mypo) then

mygs1_128(index) = mid(myLineinf,2,40)
mypeso(index) = mid(myLineinf,87,5)

index = index + 1

myitemcode = mid(myLineinf,60,5)
mygtin12 = mid(myLineinf,45,12)
sellbydate = mid(myLineinf,107,10)
packingdate = mid(myLineinf,94,10)

end if

Loop

index1 = 1
index = 1

Do While Not myFile.AtEndofStream
myLine = myFile.ReadLine

if InStr(myLine, “transaction_id='” & mypo & “‘>”) then
mypocheck = true

end if

if InStr(myLine, “itemcode”) then
myLine = ” ” & myitemcode &
“”

end if

if InStr(myLine, “plu_number”) then
myLine = ” ” & myplu &
“”

end if

if InStr(myLine, “commonname”) then
myLine = ” ” & commonname &
“”

end if

if InStr(myLine, “gtin_12″) then
myLine = ” ” & mygtin12 &
“”

end if

if InStr(myLine, “scientificname”) then
myLine = ” ” & sname &
“”

end if

if InStr(myLine, “sellbydate”) then
myLine = ” ” & sellbydate &
“”

end if

if InStr(myLine, “packagingdate”) then
myLine = ” ” & packingdate &
“”

end if

if InStr(myLine, “netweight”) and Instr(myLine,”averagenetweight”) = false
then
myLine = ” ” & mypeso(index) &
“”
index = index + 1
end if

if InStr(myLine, “gs1_128barcode”) then

myLine = ” ” &
mygs1_128(index1) & “”
index1 = index1 + 1
end if

myTemp.WriteLine myLine
Loop

myFile.Close
myTemp.Close
objFSO.DeleteFile(filePath)
objFSO.MoveFile filePath&”.tmp”, filePath

Wscript.Echo “TXT Ready”
‘***************************************************************************
******************************

Enjoy.

Posted on

10 basic examples of linux netstat command

Courtesy of http://www.binarytides.com/linux-netstat-command-examples/

Netstat

Netstat is a command line utility that can be used to list out all the network (socket) connections on a system. It lists out all the tcp, udp socket connections and the unix socket connections.

Apart from connected sockets it can also list listening sockets that are waiting for incoming connections. So by verifying an open port 80 you can confirm if a web server is running on the system or not. This makes it a very useful tool for network and system administrators.

In this tutorial we shall be checking out few examples of how to use netstat to find information about network connections and open ports on a system.

Here is a quick intro to netstat from the man pages

netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

1. List out all connections

The first and most simple command is to list out all the current connections. Simply run the netstat command with the a option.

$ netstat -a
 
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 enlightened:domain      *:*                     LISTEN     
tcp        0      0 localhost:ipp           *:*                     LISTEN     
tcp        0      0 enlightened.local:54750 li240-5.members.li:http ESTABLISHED
tcp        0      0 enlightened.local:49980 del01s07-in-f14.1:https ESTABLISHED
tcp6       0      0 ip6-localhost:ipp       [::]:*                  LISTEN     
udp        0      0 enlightened:domain      *:*                                
udp        0      0 *:bootpc                *:*                                
udp        0      0 enlightened.local:ntp   *:*                                
udp        0      0 localhost:ntp           *:*                                
udp        0      0 *:ntp                   *:*                                
udp        0      0 *:58570                 *:*                                
udp        0      0 *:mdns                  *:*                                
udp        0      0 *:49459                 *:*                                
udp6       0      0 fe80::216:36ff:fef8:ntp [::]:*                             
udp6       0      0 ip6-localhost:ntp       [::]:*                             
udp6       0      0 [::]:ntp                [::]:*                             
udp6       0      0 [::]:mdns               [::]:*                             
udp6       0      0 [::]:63811              [::]:*                             
udp6       0      0 [::]:54952              [::]:*                             
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     12403    @/tmp/dbus-IDgfj3UGXX
unix  2      [ ACC ]     STREAM     LISTENING     40202    @/dbus-vfs-daemon/socket-6nUC6CCx

The above command shows all connections from different protocols like tcp, udp and unix sockets. However this is not quite useful. Administrators often want to pick out specific connections based on protocols or port numbers for example.

2. List only TCP or UDP connections

To list out only tcp connections use the t options.

$ netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 enlightened:domain      *:*                     LISTEN     
tcp        0      0 localhost:ipp           *:*                     LISTEN     
tcp        0      0 enlightened.local:36310 del01s07-in-f24.1:https ESTABLISHED
tcp        0      0 enlightened.local:45038 a96-17-181-10.depl:http ESTABLISHED
tcp        0      0 enlightened.local:37892 ABTS-North-Static-:http ESTABLISHED
.....

Similarly to list out only udp connections use the u option.

$ netstat -au
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
udp        0      0 *:34660                 *:*                                
udp        0      0 enlightened:domain      *:*                                
udp        0      0 *:bootpc                *:*                                
udp        0      0 enlightened.local:ntp   *:*                                
udp        0      0 localhost:ntp           *:*                                
udp        0      0 *:ntp                   *:*                                
udp6       0      0 fe80::216:36ff:fef8:ntp [::]:*                             
udp6       0      0 ip6-localhost:ntp       [::]:*                             
udp6       0      0 [::]:ntp                [::]:*

The above output shows both ipv4 and ipv6 connections.

3. Disable reverse dns lookup for faster output

By default, the netstat command tries to find out the hostname of each ip address in the connection by doing a reverse dns lookup. This slows down the output. If you do not need to know the host name and just the ip address is sufficient then suppress the hostname lookup with the n option.

$ netstat -ant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
tcp        0      0 192.168.1.2:49058       173.255.230.5:80        ESTABLISHED
tcp        0      0 192.168.1.2:33324       173.194.36.117:443      ESTABLISHED
tcp6       0      0 ::1:631                 :::*                    LISTEN

The above command shows ALL TCP connections with NO dns resolution. Got it ? Good.

4. List out only listening connections

Any network daemon/service keeps an open port to listen for incoming connections. These too are like socket connections and are listed out by netstat. To view only listening ports use the l options.

$ netstat -tnl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
tcp6       0      0 ::1:631                 :::*                    LISTEN

Now we can see only listening tcp ports/connections. If you want to see all listening ports, remove the t option. If you want to see only listening udp ports use the u option instead of t.
Make sure to remove the ‘a’ option, otherwise all connections would get listed and not just the listening connections.

5. Get process name/pid and user id

When viewing the open/listening ports and connections, its often useful to know the process name/pid which has opened that port or connection. For example the Apache httpd server opens port 80. So if you want to check whether any http server is running or not, or which http server is running, apache or nginx, then track down the process name.

The process details are made available by the ‘p’ option.

~$ sudo netstat -nlpt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN      1144/dnsmasq    
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      661/cupsd       
tcp6       0      0 ::1:631                 :::*                    LISTEN      661/cupsd

When using the p option, netstat must be run with root privileges, otherwise it cannot detect the pids of processes running with root privileges and most services like http and ftp often run with root privileges.

Along with process name/pid its even more useful to get the username/uid owning that particular process. Use the e option along with the p option to get the username too.

$ sudo netstat -ltpe
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode       PID/Program name
tcp        0      0 enlightened:domain      *:*                     LISTEN      root       11090       1144/dnsmasq    
tcp        0      0 localhost:ipp           *:*                     LISTEN      root       9755        661/cupsd       
tcp6       0      0 ip6-localhost:ipp       [::]:*                  LISTEN      root       9754        661/cupsd

The above example lists out Listening connections of Tcp type with Process information and Extended information.
The extended information contains the username and inode of the process. This is a useful command for network administrators.

Note – If you use the n option with the e option, the uid would be listed and not the username.

6. Print statistics

The netstat command can also print out network statistics like total number of packets received and transmitted by protocol type and so on.

To list out statistics of all packet types

$ netstat -s
Ip:
    32797 total packets received
    0 forwarded
    0 incoming packets discarded
    32795 incoming packets delivered
    29115 requests sent out
    60 outgoing packets dropped
Icmp:
    125 ICMP messages received
    0 input ICMP message failed.
    ICMP input histogram:
        destination unreachable: 125
    125 ICMP messages sent
    0 ICMP messages failed
    ICMP output histogram:
        destination unreachable: 125
... OUTPUT TRUNCATED ...

To print out statistics of only select protocols like TCP or UDP use the corresponding options like t and u along with the s option. Simple!

7. Display kernel routing information

The kernel routing information can be printed with the r option. It is the same output as given by the route command. We also use the n option to disable the hostname lookup.

$ netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.1.1     0.0.0.0         UG        0 0          0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0

8. Print network interfaces

The netstat command can also print out the information about the network interfaces. The i option does the task.

$ netstat -i
Kernel Interface table
Iface   MTU Met   RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0       1500 0     31611      0      0 0         27503      0      0      0 BMRU
lo        65536 0      2913      0      0 0          2913      0      0      0 LRU

The above output contains information in a very raw format. To get a more human friendly version of the output use the e option along with i.

$ netstat -ie
Kernel Interface table
eth0      Link encap:Ethernet  HWaddr 00:16:36:f8:b2:64  
          inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::216:36ff:fef8:b264/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:31682 errors:0 dropped:0 overruns:0 frame:0
          TX packets:27573 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:29637117 (29.6 MB)  TX bytes:4590583 (4.5 MB)
          Interrupt:18 Memory:da000000-da020000 
 
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2921 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2921 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:305297 (305.2 KB)  TX bytes:305297 (305.2 KB)

The above output is similar to the output shown by the ifconfig command.

9. Get netstat output continuously

Netstat can output connection information continuously with the c option.

$ netstat -ct

The above command will output tcp connections continuously.

10. Display multicast group information

The g option will display the multicast group information for IPv4 and IPv6 protocols.

$ netstat -g
IPv6/IPv4 Group Memberships
Interface       RefCnt Group
--------------- ------ ---------------------
lo              1      all-systems.mcast.net
eth0            1      224.0.0.251
eth0            1      all-systems.mcast.net
lo              1      ip6-allnodes
lo              1      ff01::1
eth0            1      ff02::fb
eth0            1      ff02::1:fff8:b264
eth0            1      ip6-allnodes
eth0            1      ff01::1
wlan0           1      ip6-allnodes
wlan0           1      ff01::1

More examples of netstat command

Okay, we covered the basic examples of netstat command above. Now its time to do some geek stuff with style.

Print active connections

Active socket connections are in “ESTABLISHED” state. So to get all current active connections use netstat with grep as follows

$ netstat -atnp | grep ESTA
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
tcp        0      0 192.168.1.2:49156       173.255.230.5:80        ESTABLISHED 1691/chrome     
tcp        0      0 192.168.1.2:33324       173.194.36.117:443      ESTABLISHED 1691/chrome

To watch a continous list of active connections, use the watch command along with netstat and grep

$ watch -d -n0 "netstat -atnp | grep ESTA"

Check if a service is running

If you want to check if a server like http,smtp or ntp is running or not, use grep again.

$ sudo netstat -aple | grep ntp
udp        0      0 enlightened.local:ntp   *:*                                 root       17430       1789/ntpd       
udp        0      0 localhost:ntp           *:*                                 root       17429       1789/ntpd       
udp        0      0 *:ntp                   *:*                                 root       17422       1789/ntpd       
udp6       0      0 fe80::216:36ff:fef8:ntp [::]:*                              root       17432       1789/ntpd       
udp6       0      0 ip6-localhost:ntp       [::]:*                              root       17431       1789/ntpd       
udp6       0      0 [::]:ntp                [::]:*                              root       17423       1789/ntpd       
unix  2      [ ]         DGRAM                    17418    1789/ntpd

So we found that ntp server is running. Grep for http or smtp or whatever you are looking for.

Well, that was most of what netstat is used for. If you are looking for more advanced information or want to dig deeper, read up the netstat manual (man netstat).

Posted on

18 commands to monitor network bandwidth on Linux server

Courtesy of http://www.binarytides.com/linux-commands-monitor-network/

Interesting.

 Linux By Silver Moon On Apr 4, 2014 28 Comments

 Network monitoring on Linux

This post mentions some linux command line tools that can be used to monitor the network usage. These tools monitor the traffic flowing through network interfaces and measure the speed at which data is currently being transferred. Incoming and outgoing traffic is shown separately.

Some of the commands, show the bandwidth used by individual processes. This makes it easy to detect a process that is overusing network bandwidth.

The tools have different mechanisms of generating the traffic report. Some of the tools like nload read the “/proc/net/dev” file to get traffic stats, whereas some tools use the pcap library to capture all packets and then calculate the total size to estimate the traffic load.

Here is a list of the commands, sorted by their features.

1. Overall bandwidth - nload, bmon, slurm, bwm-ng, cbm, speedometer, netload  2. Overall bandwidth (batch style output) - vnstat, ifstat, dstat, collectl  2. Bandwidth per socket connection - iftop, iptraf, tcptrack, pktstat, netwatch, trafshow  3. Bandwidth per process - nethogs

1. Nload

Nload is a commandline tool that allows users to monitor the incoming and outgoing traffic separately. It also draws out a graph to indicate the same, the scale of which can be adjusted. Easy and simple to use, and does not support many options.

So if you just need to take a quick look at the total bandwidth usage without details of individual processes, then nload will be handy.

$ nload

Installing Nload – Fedora and Ubuntu have got it in the default repos. CentOS users need to get nload from Epel repositories.

# fedora or centos
$ yum install nload -y
 
# ubuntu/debian
$ sudo apt-get install nload

2. iftop

Iftop measures the data flowing through individual socket connections, and it works in a manner that is different from Nload. Iftop uses the pcap library to capture the packets moving in and out of the network adapter, and then sums up the size and count to find the total bandwidth under use.

Although iftop reports the bandwidth used by individual connections, it cannot report the process name/id involved in the particular socket connection. But being based on the pcap library, iftop is able to filter the traffic and report bandwidth usage over selected host connections as specified by the filter.

$ sudo iftop -n

The n option prevents iftop from resolving ip addresses to hostname, which causes additional network traffic of its own.

Install iftop – Ubuntu/Debian/Fedora users get it from default repos. CentOS users get it from Epel.

# fedora or centos
yum install iftop -y
 
# ubuntu or debian
$ sudo apt-get install iftop

3. iptraf

Iptraf is an interactive and colorful IP Lan monitor. It shows individual connections and the amount of data flowing between the hosts. Here is a screenshot

$ sudo iptraf

Install iptraf

# Centos (base repo)
$ yum install iptraf
 
# fedora or centos (with epel)
$ yum install iptraf-ng -y
 
# ubuntu or debian
$ sudo apt-get install iptraf iptraf-ng

4. nethogs

Nethogs is a small ‘net top’ tool that shows the bandwidth used by individual processes and sorts the list putting the most intensive processes on top. In the event of a sudden bandwidth spike, quickly open nethogs and find the process responsible. Nethogs reports the PID, user and the path of the program.

$ sudo nethogs

Install Nethogs – Ubuntu, Debian, Fedora users get from default repos. CentOS users need Epel

# ubuntu or debian (default repos)
$ sudo apt-get install nethogs
 
# fedora or centos (from epel)
$ sudo yum install nethogs -y

5. bmon

Bmon (Bandwidth Monitor) is a tool similar to nload that shows the traffic load over all the network interfaces on the system. The output also consists of a graph and a section with packet level details.

Install Bmon – Ubuntu, Debian and Fedora users can install from default repos. CentOS users need to setup repoforge, since its not available in Epel.

# ubuntu or debian
$ sudo apt-get install bmon
 
# fedora or centos (from repoforge)
$ sudo yum install bmon

Bmon supports many options and is capable of producing reports in html format. Check the man page for more information

6. slurm

Slurm is ‘yet’ another network load monitor that shows device statistics along with an ascii graph. It supports 3 different styles of graphs each of which can be activated using the c, s and l keys. Simple in features, slurm does not display any further details about the network load.

$ slurm -s -i eth0

Install slurm

# debian or ubuntu
$ sudo apt-get install slurm
 
# fedora or centos
$ sudo yum install slurm -y

7. tcptrack

Tcptrack is similar to iftop, and uses the pcap library to capture packets and calculate various statistics like the bandwidth used in each connection. It also supports the standard pcap filters that can be used to monitor specific connections.

Install tcptrack – Ubuntu, Debian and Fedora have it in default repos. CentOS users need to get it from RepoForge as it is not available in Epel either.

# ubuntu, debian
$ sudo apt-get install tcptrack
 
# fedora, centos (from repoforge repository)
$ sudo yum install tcptrack

8. Vnstat

Vnstat is bit different from most of the other tools. It actually runs a background service/daemon and keeps recording the size of data transfer all the time. Next it can be used to generate a report of the history of network usage.

$ service vnstat status
 * vnStat daemon is running

Running vnstat without any options would simply show the total amount of data transfer that took place since the date the daemon is running.

$ vnstat
Database updated: Mon Mar 17 15:26:59 2014
 
   eth0 since 06/12/13
 
          rx:  135.14 GiB      tx:  35.76 GiB      total:  170.90 GiB
 
   monthly
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
       Feb '14      8.19 GiB |    2.08 GiB |   10.27 GiB |   35.60 kbit/s
       Mar '14      4.98 GiB |    1.52 GiB |    6.50 GiB |   37.93 kbit/s
     ------------------------+-------------+-------------+---------------
     estimated      9.28 GiB |    2.83 GiB |   12.11 GiB |
 
   daily
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
     yesterday    236.11 MiB |   98.61 MiB |  334.72 MiB |   31.74 kbit/s
         today    128.55 MiB |   41.00 MiB |  169.56 MiB |   24.97 kbit/s
     ------------------------+-------------+-------------+---------------
     estimated       199 MiB |      63 MiB |     262 MiB |

To monitor the bandwidth usage in realtime, use the ‘-l’ option (live mode). It would then show the total bandwidth used by incoming and outgoing data, but in a very precise manner without any internal details about host connections or processes.

$ vnstat -l -i eth0
Monitoring eth0...    (press CTRL-C to stop)
 
   rx:       12 kbit/s    10 p/s          tx:       12 kbit/s    11 p/s

Vnstat is more like a tool to get historic reports of how much bandwidth is used everyday or over the past month. It is not strictly a tool for monitoring the network in real time.

Vnstat supports many options, details about which can be found in the man page.

Install vnstat

# ubuntu or debian
$ sudo apt-get install vnstat
 
# fedora or centos (from epel)
$ sudo yum install vnstat

9. bwm-ng

Bwm-ng (Bandwidth Monitor Next Generation) is another very simple real time network load monitor that reports a summary of the speed at which data is being transferred in and out of all available network interfaces on the system.

$ bwm-ng
bwm-ng v0.6 (probing every 0.500s), press 'h' for help
  input: /proc/net/dev type: rate
  /         iface                   Rx                   Tx                T
ot==========================================================================
==           eth0:           0.53 KB/s            1.31 KB/s            1.84
KB             lo:           0.00 KB/s            0.00 KB/s            0.00
KB--------------------------------------------------------------------------
--          total:           0.53 KB/s            1.31 KB/s            1.84
KB/s

If the console size is sufficiently large, bwm-ng can also draw bar graphs for the traffic using the curses2 output mode.

$ bwm-ng -o curses2

Install Bwm-NG – On CentOS bwm-ng can be installed from Epel.

# ubuntu or debian
$ sudo apt-get install bwm-ng
 
# fedora or centos (from epel)
$ sudo apt-get install bwm-ng

10. cbm – Color Bandwidth Meter

A tiny little simple bandwidth monitor that displays the traffic volume through network interfaces. No further options, just the traffic stats are display and updated in realtime.

$ sudo apt-get install cbm

11. speedometer

Another small and simple tool that just draws out good looking graphs of incoming and outgoing traffic through a given interface.

$ speedometer -r eth0 -t eth0

Install speedometer

# ubuntu or debian users
$ sudo apt-get install speedometer

12. Pktstat

Pktstat displays all the active connections in real time, and the speed at which data is being transferred through them. It also displays the type of the connection, i.e. tcp or udp and also details about http requests if involved.

$ sudo pktstat -i eth0 -nt

$ sudo apt-get install pktstat

13. Netwatch

Netwatch is part of the netdiag collection of tools, and it too displays the connections between local host and other remote hosts, and the speed at which data is transferring on each connection.

$ sudo netwatch -e eth0 -nt

$ sudo apt-get install netdiag

14. Trafshow

Like netwatch and pktstat, trafshow reports the current active connections, their protocol and the data transfer speed on each connection. It can filter out connections using pcap type filters.

Monitor only tcp connections

$ sudo trafshow -i eth0 tcp

$ sudo apt-get install netdiag

15. Netload

The netload command just displays a small report on the current traffic load, and the total number of bytes transferred since the program start. No more features are there. Its part of the netdiag.

$ netload eth0

$ sudo apt-get install netdiag

16. ifstat

The ifstat reports the network bandwidth in a batch style mode. The output is in a format that is easy to log and parse using other programs or utilities.

$ ifstat -t -i eth0 0.5
  Time           eth0       
HH:MM:SS   KB/s in  KB/s out
09:59:21      2.62      2.80
09:59:22      2.10      1.78
09:59:22      2.67      1.84
09:59:23      2.06      1.98
09:59:23      1.73      1.79

Install ifstat – Ubuntu, Debian and Fedora users have it in the default repos. CentOS users need to get it from Repoforge, since its not there in Epel.

# ubuntu, debian
$ sudo apt-get install ifstat
 
# fedora, centos (Repoforge)
$ sudo yum install ifstat

17. dstat

Dstat is a versatile tool (written in python) that can monitor different system statistics and report them in a batch style mode or log the data to a csv or similar file. This example shows how to use dstat to report network bandwidth

$ dstat -nt
-net/total- ----system----
 recv  send|     time     
   0     0 |23-03 10:27:13
1738B 1810B|23-03 10:27:14
2937B 2610B|23-03 10:27:15
2319B 2232B|23-03 10:27:16
2738B 2508B|23-03 10:27:17

Install dstat

$ sudo apt-get install dstat

18. collectl

Collectl reports system statistics in a style that is similar to dstat, and like dstat it is gathers statistics about various different system resources like cpu, memory, network etc. Over here is a simple example of how to use it to report network usage/bandwidth.

$ collectl -sn -oT -i0.5
waiting for 0.5 second sample...
#         
#Time       KBIn  PktIn  KBOut  PktOut 
10:32:01      40     58     43      66 
10:32:01      27     58      3      32 
10:32:02       3     28      9      44 
10:32:02       5     42     96      96 
10:32:03       5     48      3      28

Install Collectl

# Ubuntu/Debian users
$ sudo apt-get install collectl
 
#Fedora
$ sudo yum install collectl

Summary

Those were a few handy commands to quickly check the network bandwidth on your linux server. However these need the user to login to the remote server over ssh. Alternatively web based monitoring tools can also be used for the same task.

Ntop and Darkstat are some of the basic web based network monitoring tools available for Linux. Beyond these lie the enterprise level monitoring tools like Nagios that provide a host of features to not just monitor a server but entire infrastructure.

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The Technology Journey Begins

Thanks for joining me!

Good company in a journey makes the way seem shorter. — Izaak Walton

This Blog it is to share my passion for the Technology, if you are a technology person lets share some content and information for the mutual grow.

Ronald Blanco

 

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Cron on freeBSD

 cron(8)

Contributed by Tom Rhodes.
One of the most useful utilities in FreeBSD is cron. This utility runs in the background and regularly checks /etc/crontab for tasks to execute and searches/var/cron/tabs for custom crontab files. These files are used to schedule tasks which cron runs at the specified times. Each entry in a crontab defines a task to run and is known as a cron job.
Two different types of configuration files are used: the system crontab, which should not be modified, and user crontabs, which can be created and edited as needed. The format used by these files is documented in crontab(5). The format of the system crontab, /etc/crontab includes a who column which does not exist in user crontabs. In the system crontab, cron runs the command as the user specified in this column. In a user crontab, all commands run as the user who created the crontab.
User crontabs allow individual users to schedule their own tasks. The root user can also have a user crontab which can be used to schedule tasks that do not exist in the system crontab.
Here is a sample entry from the system crontab, /etc/crontab:
# /etc/crontab - root's crontab for FreeBSD
#
# $FreeBSD: head/en_US.ISO8859-1/books/handbook/config/chapter.xml 45038 2014-06-09 03:58:34Z wblock $
# 1
SHELL=/bin/sh
PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin 2
#
#minute hour mday month wday who command 3
#
*/5 * * * * root /usr/libexec/atrun 4

1
Lines that begin with the # character are comments. A comment can be placed in the file as a reminder of what and why a desired action is performed. Comments cannot be on the same line as a command or else they will be interpreted as part of the command; they must be on a new line. Blank lines are ignored.
2
The equals (=) character is used to define any environment settings. In this example, it is used to define the SHELL and PATH. If the SHELL is omitted, cron will use the default Bourne shell. If the PATH is omitted, the full path must be given to the command or script to run.
3
This line defines the seven fields used in a system crontab: minute, hour, mday, month, wday, who, and command. The minute field is the time in minutes when the specified command will be run, the hour is the hour when the specified command will be run, the mday is the day of the month, month is the month, and wday is the day of the week. These fields must be numeric values, representing the twenty-four hour clock, or a *, representing all values for that field. The who field only exists in the system crontab and specifies which user the command should be run as. The last field is the command to be executed.
4
This entry defines the values for this cron job. The */5, followed by several more * characters, specifies that /usr/libexec/atrun is invoked by root every five minutes of every hour, of every day and day of the week, of every month.
Commands can include any number of switches. However, commands which extend to multiple lines need to be broken with the backslash “\” continuation character.