@drysdalk

Your solution is functional but can I make a few suggestions to help improve it.

Code:

file_string=`/bin/cat date.txt | /usr/bin/awk '{print $5,$4,$7,$6,$8}'`

1. Awk can open an read files without the help of cat
2. No need to change order of the fields GNU date would accept a date in the format anyway.
3. OP requires matching on line containing "After :"

Perhaps: file_string=$(awk -F": " '/After :/ {print $2}')

Code:

if [ "$file_epoch" -gt "$now_epoch" ]
then
        #let difference=$file_epoch-$now_epoch
        difference=`/usr/bin/expr $file_epoch - $now_epoch`
elif [ "$now_epoch" -gt "$file_epoch" ]
then
        #let difference=$now_epoch-$file_epoch
        difference=`/usr/bin/expr $now_epoch - $file_epoch`
else
        let difference=0
fi

OP is only wanting to match a filedate older than 2 days, the code above would also match filedate up to 2 days in the future.

OP was already using Arithmetic Expansion to calculate differences between epoch times.
I believe $((expression)) is superior to let as its more portable and is much better than using /usr/bin/expr as this wastes resources starting a new process and loading the expr command binary into memory to execute it.

I'd simply go with:

Code:

if (( file_epoch < now_epoch - 2*24*60*60 ))
then
 echo Date Less then 2 days
else
 echo Date Greater then 2 days
fi