Category Archives: sysadmin

Linux, sysadmin

Using swatch to Monitor Logfiles

A very useful tool for monitoring logfiles is Swatch (aka Simple WATCHer of Logfiles). This is a perl program that essentially watches a logfile. You can run as many instances of it as you want, but you can only watch one logfile per instance. Depending on the log file you want to watch, you may have to run swatch with some additional privilege. For instance, /var/log/messages is likely to be the primary target for anyone interested in using swatch. But this file should be readable

firewall, pfsense, sysadmin

USEFUL PFSENSE COMMANDS

Description Command
Reload the Firewall with all the configuration. This also restarts the webgui and sshd – but keeps the current ssh sessions active just as a regular sshd restart. /etc/rc.reload_all
Manually edit the configuration in /conf/config.xml. Once file has been saved and editor exited, the /tmp/config.cache is removed so the next config reload event will load config.xml, not the cached version. You could run the next command to trigger an instant reload. viconfig                                                                                                 
Shows the current state table pfctl -ss
Shows current filter rules pfctl -sr
Show as much as possible. pfctl -sa
Shows current NAT rules pfctl -sn
Activate the pf packet filter – enables all fw functions pfctl -e
Deactivate the pf packet filter – disables all fw functions pfctl -d

PFSense: How to add firewall rule at the command line?

There is a command line available in PFSense firewall to allow you to add firewall rules. In the event of  locked out from firewall due to miss configuration of firewall rules, you may use command line “easyrule” to add firewall rules to let you get in to firewall again.

Below are the syntax and example of easyrule command:-

Syntax EasyRule function

easyrule pass/block <interface> <protocol> <source IP> <destination ip> [destination port]

Example:

easyrule pass wan tcp 0.0.0.0/0 192.168.0.1 80
easyrule pass wan icmp 1.1.1.1 192.168.0.1
easyrule block wan 1.1.1.1
Computer, NowYouKnow, Open Source, Photography, Photoshop, Software, sysadmin, Tech, Tips, video

How to rotate and flip videos using Handbrake – IT Support Guides

How to rotate and flip videos using Handbrake

HandBrake is a free tool that’s available for Windows, Mac OS and Ubuntu that allows you to take a video in various formats and convert it to an MP4.

The steps below show how to rotate the video being processed.

Before beginning, you need to download and install HandBrake.

  1. Open HandBrake and load your video using the ‘Source’ button to select the video you want to rotate or flip
  2. Choose where to save the rotated video by clicking on the ‘Browse’ button to select where the converted file will be saved.
  3. Open the ‘Filters’ tab
  5. The ‘Rotate’ option allows you to choose four different options
    1. 0 – do nothing
    2. 90 – rotate to the right
    3. 180 – turn upside down
    4. 270 – rotate to the left
  6. Choose the rotate option you require
  7. Click ‘Start Encode’ to begin
  8. At the bottom of the window you will see the progress

 

Help! It didn’t work

Try the manual way of rotating, by applying manual filters.

  1. Open the ‘Video’ tab
  2. We’ll be working with the ‘Extra Options’ setting.
  3. Once you have the required command entered, click ‘Start Encode’ to begin.
  4.  

Rotate 90 degrees clockwise

To rotate 90 degrees clockwise, enter the following command into the ‘Extra Options’ setting:

, --rotate=4

Rotate 90 degrees anti-clockwise

To rotate 90 degrees anti-clockwise, enter the following command into the ‘Extra Options’ setting:

, --rotate=7

Rotate 180 degrees (upside down)

To rotate 180 degrees so that the video is upside down, enter the following command into the ‘Extra Options’ setting:

, --rotate=3

Other options?

The official HandBrake documentation has more detail on what other options are available.

1 : x flip
2 : y flip
3 : 180 degrees rotate (also the DEFAULT)
4 : 90 degrees rotate (clockwise)
5 : 90 degrees rotate + y flip
6 : 270 degrees rotate + y flip
7 : 270 degrees rotate

Source: How to rotate and flip videos using Handbrake – IT Support Guides

Linux, sysadmin

How to: Purge, Flush or Delete Postfix Queue, or a Single Email

How to: Purge, Flush or Delete Postfix Queue, or a Single Email

Written by 
Date: 2012-04-25 14:53:30 00:00

To flush or purge the postfix mail queue, just enter this command

postfix -f

But if you need to delete an individual email from the queue, you’ll first need to see the queue. Traditionally you use mailq this time we’ll use:

postqueue -p

And the output should show all messages in queue:

5642B4D8647* 1683500 Tue Jun  3 08:37:27  xxxxxx@xxxxxxx.com
                                         rrrrrrrrr@hotmail.com

9359B4D82B1* 1635730 Tue Jun  3 08:36:53  xxxxxx@xxxxxxx.com
                                         yyyyyyyy@hotmail.com

The first number is the message ID, if you only want to delete one of them, enter:

postsuper -d 5642B4D8647

That will only delete one email for the queue, that specific email you want to delete from it.

If you want to delete all deferred mails, you can use:

postsuper -d deferred

Source: How to: Purge, Flush or Delete Postfix Queue, or a Single Email