Create backup copy of file, adding suffix of the date of the file modification (NOT today's date)

cp file file.$(date -d @$(stat -c '%Y' file) "+%y%m%d")
When I go to change a configuration file I always like to make a backup first. You can use "cp -p" to preserve the modification time, but it gets confusing to have file.prev, file.prev2, etc. So I like to add a YYMMDD suffix that shows when the file was last changed. "stat -c %Y" gives you the modification time in epoch seconds, then "date -d @" converts that to whatever format you specify in your "+format" string.
Sample Output
# ls -l
-rw-r--r-- 1 root root 0 Dec 31  2018 file
# cp -p file file.$(date -d @$(stat -c '%Y' file) "+%y%m%d")
 ls -l
-rw-r--r-- 1 root root 0 Dec 31  2018 file
-rw-r--r-- 1 root root 0 Dec 31  2018 file.181231

By: dmmst19
2019-07-18 18:09:09

2 Alternatives + Submit Alt

What Others Think

Just found a site a could relate to home care spokane
aegyjingoo · 34 weeks and 1 day ago
When was this?
geebranz · 28 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.


Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: