Find the files that have been changed in last 24 hours

To find all files modified in the last 24 hours (last full day) in a particular specific directory and its sub-directories:

find /directory_path -mtime -1 -ls

Should be to your liking

The - before 1 is important - it means anything changed one day or less ago. A + before 1 would instead mean anything changed at least one day ago, while having nothing before the 1 would have meant it was changed exacted one day ago, no more, no less.

Another, more humane way:

find /<directory> -newermt "-24 hours" -ls

or:

find /<directory> -newermt "1 day ago" -ls

or:

find /<directory> -newermt "yesterday" -ls

You can do that with

find . -mtime 0

From man find:

[The] time since each file was last modified is divided by 24 hours and any remainder is discarded. That means that to match -mtime 0, a file will have to have a modification in the past which is less than 24 hours ago.