dp

dp generates predictable duplicate names, like duplicating an item in a file manager.

It can duplicate files and directories itself, or provide the destination for use with another tool.

Installation

go install github.com/CatsDeservePets/dp@latest

Usage

usage: dp [-n] [-v] source ...
       dp -g source

  -g	generate a duplicate pathname and write it to standard output
  -n	do not duplicate files, but show what would be done instead; implies -v
  -v	cause dp to be verbose, showing files as they are duplicated

Semantics

By default, dp uses Finder-like duplicate names:

file.txt        -> file copy.txt
file copy.txt   -> file copy 2.txt
file copy 2.txt -> file copy 3.txt

Path contents are duplicated roughly like cp -R: directories are traversed recursively, symlinks are not followed, and regular files are copied. For files, the source mode is modified by the process umask. Created directories have the same mode as their source after their contents have been copied. Ownership, timestamps, ACLs, and extended attributes are not preserved.

Each command-line argument is handled independently. If a source cannot be duplicated, dp reports the error and continues with the next argument. An error during copying may leave a partially copied duplicate in place.

For more control over copying, use -g and pass the resulting pathname to another tool:

src="$1"
dst=$(dp -g "$src") || exit
cp -Rp "$src" "$dst"

Naming

Duplicate names can be configured using the environment variables $DUPFMT_FIRST and $DUPFMT_NUMBERED.

The following placeholders are supported:

%f    file name, including extension
%b    file stem, i.e. file name without extension
%e    extension, including the dot
%n    duplicate number

$DUPFMT_FIRST describes the first duplicate name and must not contain %n. $DUPFMT_NUMBERED describes the numbered names that follow and must contain exactly one %n, preceded by fixed text.

Both formats must use the same shape: either %f for the whole file name, or %b and %e for stem and extension.

When splitting a file name, the extension starts at the first dot after any leading dots:

archive.tar.gz -> archive copy.tar.gz
.bashrc        -> .bashrc copy

Example formats

Finder-like (default):

DUPFMT_FIRST="%b copy%e"
DUPFMT_NUMBERED="%b copy %n%e"

file.txt -> file copy.txt -> file copy 2.txt

Explorer-like:

DUPFMT_FIRST="%b - Copy%e"
DUPFMT_NUMBERED="%b - Copy (%n)%e"

file.txt -> file - Copy.txt -> file - Copy (2).txt

Nautilus-like:

DUPFMT_FIRST="%b (Copy)%e"
DUPFMT_NUMBERED="%b (Copy %n)%e"

file.txt -> file (Copy).txt -> file (Copy 2).txt

Emacs-like:

DUPFMT_FIRST="%f.~1~"
DUPFMT_NUMBERED="%f.~%n~"

file.txt -> file.txt.~1~ -> file.txt.~2~