Shell – Copy a file and append a timestamp

datefile-copyshell-scripttimestamps

I've got two issues with my script that copies files and adds a timestamp to the name.

cp -ra /home/bpacheco/Test1 /home/bpacheco/Test2-$(date +"%m-%d-%y-%T")

The above adds Test2 as the filename, but I want it to keep the original source file's file name which in this example is named Test.

cp -ra /home/bpacheco/Test1 /home/bpacheco/Test2-$(date +"%m-%d-%y-%r")

The other issue is when I add the %r as the timestamp code I get the error stating that target "PM" is not a directory. I'm trying to get the timestamp as 12-hour clock time.

Best Answer

One of your problems is that you left out the double quotes around the command substitution, so the output from the date command was split at spaces. See Why does my shell script choke on whitespace or other special characters? This is a valid command:

cp -a /home/bpacheco/Test1 "/home/bpacheco/Test2-$(date +"%m-%d-%y-%r")"

If you want to append to the original file name, you need to have that in a variable.

source=/home/bpacheco/Test1
cp -a -- "$source" "$source-$(date +"%m-%d-%y-%r")"

If you're using bash, you can use brace expansion instead.

cp -a /home/bpacheco/Test1{,"-$(date +"%m-%d-%y-%r")"}

If you want to copy the file to a different directory, and append the timestamp to the original file name, you can do it this way — ${source##*/} expands to the value of source without the part up to the last / (it removes the longest prefix matching the pattern */):

source=/home/bpacheco/Test1
cp -a -- "$source" "/destination/directory/${source##*/}-$(date +"%m-%d-%y-%r")"

If Test1 is a directory, it's copied recursively, and the files inside the directory keep their name: only the toplevel directory gets a timestamp appended (e.g. Test1/foo is copied to Test1-05-10-15-07:19:42 PM). If you want to append a timestamp to all the file names, that's a different problem.

Your choice of timestamp format is a bad idea: it's hard to read for humans and hard to sort. You should use a format that's easier to read and that can be sorted easily, i.e. with parts in decreasing order of importance: year, month, day, hour, minute, second, and with a separation between the date part and the time part.

cp -a /home/bpacheco/Test1 "/home/bpacheco/Test2-$(date +"%Y%m%d-%H%M%S")"
cp -a /home/bpacheco/Test1 "/home/bpacheco/Test2-$(date +"%Y-%m-%dT%H%M%S%:z")"
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