How to add text at the end of each line after skipping Last N characters - linux

Question

I'm on Linux command line and I have log file with following content
Subscription Service Shutdown at 9:59PM UTC
Subscription Service Restarted at 11:57PM UTC
I want to add date before Time Stamp for every line
Subscription Service Shutdown at 01 Oct 2016 9:59PM UTC
Subscription Service Restarted at 01 Oct 2016 11:57PM UTC

Answer 1

the vim way:
:%s/ at /&knownString/

Answer 2

Something like this:
sed -r "s/([0-9]+{1}:[0-9]+{1}[A-Z]{2}.*$)/01 Oct 2016 \1/g" test.txt > new.txt
Where text.txt is your log file and "01 Oct 2016 " is your text and the \1 is the time inserted back in from the group match.

Answer 3

you can try something like this;
echo "Subscription Service Shutdown at 9:59PM UTC" | sed "s/at */at $(date '+%Y %b %d') /"
Eg;
$ echo "Subscription Service Shutdown at 9:59PM UTC" | sed "s/at */at $(date '+%Y %b %d') /"
Subscription Service Shutdown at 2016 Nov 08 9:59PM UTC

Answer 4

Different ways to do it in vim
1) add string after at
:%s/at \zs/01 Oct 2016 /
2) Find time string of the format HH:MM followed by AM UTC or PM UTC and add string. Add $ anchor if you need to match only at end of line
:%s/\v(\d{1,2}:\d{1,2}[AP]M UTC)/01 Oct 2016 \1/