Mv: add number to file name if the target exists

mvrename

I'm moving a file to a different folder and would like to add some kind of index to the newly moved file if a file with the same name exists already (the old one should remain untouched). For example, if file.pdf existed I would prefer something like file1.pdf or file_1.pdf for the next file with the same name.

Here I've found a variant for the opposite idea — but I don't want to make a "backup".

Does mv have some parameters out of the box for that scenario? I use Ubuntu Linux.

Best Answer

As the answer to the question you linked already states, mv can suffix files that would otherwise get overwritten by the file you move with a number to give them a unique file name:

mv --backup=t <source_file> <dest_file>

The command works by appending the next unused number suffix to the file that was first in the destination directory. The file you are moving will keep its original name.

However, this will appends suffixes like .~1~, which seems to be not what you want:

$ ls
file.pdf
file.pdf.~1~
file.pdf.~2~

You can rename those files in a second step though to get the names in a format like file_1.pdf instead of file.pdf.~1~, e.g. like this:

rename 's/((?:\..+)?)\.~(\d+)~$/_$2$1/' *.~*~

This takes all files that end with the unwanted backup suffix (by matching with the shell glob *.~*~) and lets the rename tool try to match the regular expression ((?:\..+)?)\.~(\d+)~$ on the file name. If this matches, it will capture the index from the .~1~-like suffix as second group ($2) and optionally, if the file name has an extension before that suffix like .pdf, that will be captured by the first group ($1). Then it replaces the complete matched file name part with _$2$1, inserting the captured values instead of the placeholders though.

Basically it will rename e.g. file.pdf.~1~ to file_1.pdf and something.~42~ to something_42, but it can not detect whether a file has multiple extensions, so e.g. archive.tar.gz.~5~ would become archive.tar_5.gz

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