Aschenblog: Thoughts on Code and Fabrication

Renumber Filenames Sequentially

renumber is a small command line utility that renames files in a single directory. Files are sorted in lexicographic order and then renamed with sequential numbers. It is possible to specify a prefix and suffix - these are optional parameters. There are a couple of examples of usage below.

The code is open source and available on GitHub.

Command Line Usage

$ renumber <directory> <prefix> <suffix>

Installation

The tool requires that Ruby is installed. If so, install renumber with the following command:

$ gem install renumber

Use case

I developed renumber so that I could renumber thousands images from a digital camera for use in a time lapse movie. The tool I used to stitch these images together into a movie (called ffmpeg) died if the file names had a gap (e.g. …, IMG2047, IMG2049, IMG2050, …).

The renumber tool solved this problem by renumbering the files to not have gaps.

Simple Usage

Let’s take a directory with several non-sequential files:

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drwxr-xr-x  15 troy  staff  510 Jun 17 20:12 .
drwx------+  7 troy  staff  238 Jun 17 20:06 ..
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 03.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 04.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 07.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 09.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 10.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 11.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 13.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 15.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 17.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 19.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 20.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 22.txt
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 99.txt

Let’s change to that directory and run the following:

$ renumber .

Here’s the directory listing after running the command:

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drwxr-xr-x  15 troy  staff  510 Jun 17 20:14 .
drwx------+  7 troy  staff  238 Jun 17 20:06 ..
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 00
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 01
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 02
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 03
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 04
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 05
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 06
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 07
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 08
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 09
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 10
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 11
-rw-r--r--   1 troy  staff    3 Jun 17 20:12 12

Prefix and Suffix

Let’s take the same initial file list as the above example. Let’s add a prefix and suffix:

$ renumber . foo .text

Here’s the directory listing after running the command:

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drwxr-xr-x  15 troy  staff  510 Jun 17 20:17 .
drwx------+  7 troy  staff  238 Jun 17 20:06 ..
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo00.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo01.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo02.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo03.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo04.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo05.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo06.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo07.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo08.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo09.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo10.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo11.text
-rw-r--r--   1 troy  staff    3 Jun 17 20:16 foo12.text

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