The script (ipchangemail.sh)

#!/bin/bash 

# Check if IP-address has changed. If a change has occured, mail me the new address
# Add the following line to crontab if you would like it to be run every 5 minutes:
# */5 * * * * ./ipchangemail.sh

# The network interface I want to monitor
NET_INTERFACE=eth0

# File to keep the latest IP address
IP_FILE=myip.txt

# Mail to this address when a change occur
MAILTO=mail@example.com

# Read the previous IP address from file
source $IP_FILE

CURRENT_IP=`/sbin/ifconfig $NET_INTERFACE | sed -n "/inet addr:.*255.255.25[0-5].[0-9]/{s/.*inet addr://; s/ .*//; p}"`

if [ "$CURRENT_IP" != "$OLD_IP" ]
then
        # Send email about address change
        `echo "New IP address detected: $CURRENT_IP" | mail -s "New IP address" $MAILTO`

        # Write new address to file
        `echo "OLD_IP=$CURRENT_IP" > $IP_FILE`
fi

The script can be downloaded here.

Add the following lines in the mysqld section

[mysqld]
query-cache-type = 1
query-cache-size = 10M

restart the mysql daemon

# /etc/init.d/mysql restart

Verify that query caching is enabled

# mysql -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 33499
Server version: 5.0.32-Debian_7etch6-log Debian etch distribution

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> SHOW VARIABLES LIKE '%query_cache%';
+------------------------------+----------+
| Variable_name                | Value    |
+------------------------------+----------+
| have_query_cache             | YES      |
| query_cache_limit            | 1048576  |
| query_cache_min_res_unit     | 4096     |
| query_cache_size             | 10485760 |
| query_cache_type             | ON       |
| query_cache_wlock_invalidate | OFF      |
+------------------------------+----------+
6 rows in set (0.00 sec)

If you see something like the out above, caching is enabled.

Rename files using wildcard pattern

This is the files we are going to rename

20080102-1201_DSC_0910.JPG
20080105-1923_DSC_1006.JPG
20080111-1220_DSC00189.JPG
20080122-0929_DSC00190.JPG

The mmv command is a command that lets you move/copy/append/link multiple files by wildcard patterns. It can be installed in Debian (or Debian based distributions like Ubuntu) by issuing the command

# aptitude install mmv

Now rename the files back to their original name

# mmv "*_DSC*" "DSC#2"

The result after this operation looks like this

DSC_0910.JPG
DSC_1006.JPG
DSC_1179.JPG
DSC_1302.JPG
DSC_1587.JPG

Correct the EXIF timestamp using exiv2

Next adjust the EXIF information stored in the image files to fix the one hour difference. This can be done using different EXIF tools like exiftool, but I will show you how it can be done using jhead and exiv2. The advantage with exiv2 is that it can also handle Nikon NEF files while jhead only can prosess JPG.

The current timestamp can be determined as follows

# exiftool DSC_0910.JPG | grep "File Mo"

The result in this case is

File Modification Date/Time : 2008:01:02 08:34:09

Adjust EXIF time info one hour forward using exiftool

# exiftool -AllDates+=1 DSC_0910.JPG

Other tools that could have done the job

Adjust EXIF time info one hour forward using jhead

# jhead -ta +1 DSC_0910.JPG

Install the jhead package using aptitude as mentioned earlier for the mmv package

Adjust EXIF time info one hour forward using exiv2

# exiv2 ad -a 1 DSC_0910.JPG

Rename files back to YYYYMMDD-HHMM_Original_Filename.JPG

It is now time to rename the files back to the YYYYMMDD-HHMM_Original_Filename.JPG format I used before this operation. This operation has been describe in a previous post named Rename image files according to EXIF date

exiv2 -r'%Y%m%d-%H%M_:basename:' rename $(ls D*)

The script

#!/bin/bash -x
# Needed software:
# exiftool
# exiv2
# mmv

# Script tested on Nikon D80 and Sony Cybershot DSC-W12 files

# Make a printout of how the files look like now
ls -l > repair_name_and_exif_before.txt

# Rename files to remove date formatting back to original name
mmv "*_DSC*" "DSC#2"

# Change EXIF info on JPG files (order is important)
exiftool -overwrite_original -AllDates+=1 D*.JPG
# Preserve date/time of original file when writing
exiftool -overwrite_original '-DateTimeOriginal>FileModifyDate' D*.JPG

# Change EXIF info on NEF files (order is important)
exiftool -overwrite_original -AllDates+=1 '-DateTimeOriginal>FileModifyDate' D*.NEF
# Preserve date/time of original file when writing
exiftool -overwrite_original '-DateTimeOriginal>FileModifyDate' D*.NEF

# Rename files back to date formatting (YYYYMMDD-HHMM_Filename) based on the new EXIF info
exiv2 -r'%Y%m%d-%H%M_:basename:' rename $(ls D*)

# Make a printout of how the files look like after conversion
ls -l > repair_name_and_exif_after.txt

The result after this HOWTO should look something like this spring image taken some days ago. Not one of my best photos but it will do the job in this post.

1. Open the IR photo file in Photoshop, presumeably a RAW file. In my case a Nikon NEF-file.
2. Open the file whith the White Balance set “As shot”.

3. The photo might look something like this

4. Go to the menu and choose Image –> Adjustments –> Channel Mixer… Now you can change the Red Output Channel and set the value for Red to 0% and change the Blue value to 100%. On the Blue Output Channel you set the blue Source Channel to 0% and Red to 100%.
   
5. Now we will let Photoshop adjust the levels and colors using the menu Image –> Adjustments –> Auto Levels followed by Image –> Adjustments –> Auto Color.
6. The result image should look something like this
   

Thats all that is needed to swap or invert two color channels in Photoshop CS3.

This HOWTO has not been tested on on earlier versions of Photoshop but I guess the features I’ve used aren’t new.