Update: If I am wrong with this answer please let me now.
I'm not sure if file system's modification date metadata is equivalent to exitf modification date metadata. I tested with exiftool and the dates are equivalent, so it makes me think is I can use touch for manipulating that metadata.
Solution:
First you should get the modification date of the file by using stat command:
filedate=$(stat -c '%y' "/path/to/file" | cut -d' ' -f1)
Now it will be replaced the month with another one. For that, you can use awk:
newDate=$(awk -v month="Jun" -F '-' '{print $1"-"month"-"$3}' <<< $filedate )
And with touch command you can change the creationmodification date:
touch -m -d $newDate /path/to/file
#-m argument is used to change modification time
#-d is used to specify the new date
Finally, if you want to change files recursively you can use find and the code provided before should be in a script file:
script.sh:
#! /usr/bin/env bash
filedate=$(stat -c '%y' "$1" | cut -d' ' -f1)
newMonth="Dec" #here you specify the month
newDate=$(awk -v month=$newMonth -F '-' '{print $3"-"month"-"$1}' <<< $filedate )
touch -m -d $newDate $1
And with find you can use:
find /path/to/your_directory -type f -exec ./script.sh {} \;
If you want to specify the month in the find command, you can pass it to the script.sh as parameter:
Therefore, the code would now became:
script.sh
#! /usr/bin/env bash
filedate=$(stat -c '%y' "$1" | cut -d' ' -f1)
newMonth="$2"
newDate=$(awk -v month=$newMonth -F '-' '{print $3"-"month"-"$1}' <<< $filedate )
touch -m -d $newDate $1
find command
find . -type f -exec ./script {} "Nov" \;