I don't know how to highlight the day in the year calendar cal -y with just regular expressions, but the reason your example was not working for single digit dates is because $(date +%e) prepends a space to the output when the date has a single digit.
This will work:
cal | grep --color -EC6 "\b$(date +%e | sed "s/ //g")"
This is cheating a bit, but it works.
First create an empty reference file with a specific timestamp, namely midnight:
touch -d "$(date +%FT00:00:00)" /tmp/midnight
Then find files that are newer than this file:
find . -type f -newer /tmp/midnight
If you want ls-like output from find rather than just the pathnames:
find . -type f -newer /tmp/midnight -ls
If you want to find files matching the pattern XYZ.LOG*:
find . -type f -name 'XYZ.LOG*' -newer /tmp/midnight -ls
If you have GNU find, you may bypass the temporary file and use
find . -type f -newermt 0
to get files modified since midnight.
Related: Why *not* parse `ls`?
Best Answer
You can use
man lsand here you can find--time-styleparameter. Or you can use:ls --full-time.