File Naming Convention

Purpose

Look at the file names

untitled.txt
lib.zip
123.doc
tmp.txt
myidea.txt

Even if we can remember the content of the files temporarily, we will forget soon.

A good file naming convention is good for organizing and retrieving our documents efficiently.

How To Name Files?

The most important things to remember about file naming are to be consistent and descriptive in naming and organizing your files so that it’s obvious where to find a file and what it contains. (From File naming convention in Purdue Libraries)

Step 1 Decide the Information A File Name Should Express

It varies from fields/projects to fields/projects we are working on.

It is suggested to include the information which indicates the content of the file. If we are cooperating with many others, it is also needed to distinguish our files from others’.

We can think of following information, each is regarded as a segment which will be used in Step 2.

Name of organization
Date or date range
Author
Name of project or program
Type of document, such as “Report”, “Proposal” and “Invoice” etc.
Spatial data
Language of content
Version number of file

Step 2 Decide the Sequence of Each Segment

Suppose we have decided the segments and their corresponding orders as following

Date the file created
Name of project
Type of document

The sequence should be decided based on how we retrieve documents. For example, if you are doing research and care about the chronological order, put Date as the first segment in a file name will be a good choice.

Organizational structure can play an important role in deciding the sequence. In a functional structured organization, Name of project is usually not the first segment since most work is not organized by projects.

If directory is used to organize files, the sequence of segments in the file name can be changed or the segments can even be ignored, since we can distinguish files from directory structure at first.

Step 3 Make File Naming Convention

Decide how to concatenate the sequence of segments defined in Step 2, and decide more naming rules include

Case (lowercase or uppercase)
Allowed characters in the file name
Acronyms table

For example, we decide to use underscore to concatenate segments

DateCreated_ProjectName_TypeOfDocument[_ContentSummary].FileExtension

CamelCase is used in each segment when necessary
Only alphabetic characters are allowed in each segment
No acronym is used

A valid file name is

20180810_KiteRunner_Report_ReaderFeedbackAnalysis.pdf

An invalid file name is 2018010_Kite Runner_Report_Reader Feedback Analysis.pdf since it has spaces.

Make sure everyone understand file naming convention, and follow it.

Exceptional cases are allowed in real situation, as the Done Manifesto declares, Done is better than perfect.

Tips

Have Several Naming Conventions in One Team/Project

It’s quite possible that in the same team/project, we have several naming conventions for different document types. Date is better to be included in the name of documents for meeting summary while it is not important for document like business plan in a project.

Special Characters

A number of characters are reserved in some operating file systems. Following characters are disallowed in Windows (See Naming convention in Windows), while some of them can be used in Mac. If we are not sure the operating file systems our teammates use, avoid using following characters.

< (less than)
> (greater than)
: (colon)
” (double quote)
/ (forward slash)
\ (backslash)
| (vertical bar or pipe)
? (question mark)
* (asterisk)

It’s better to define whitelist instead of blacklist.

Hyphen (Dash) and Underscore

In programming language, hyphen (dash) in a file name might not be correctly recognized. For example, python can not import module with dash in filename (See issue Can not import a module with DASH in filename) although it’s documented behavior.

For software engineers, it’s recommended to use Underscore instead of Hyphen (Dash) in naming source code files.

Spaces

Spaces are generally disallowed in file name. Although spaces are good for reading by human beings, it’s not good for computers. Many systems/software can not properly handle spaces in file names.

DO NOT make file names too long

Long file name is not supported in some systems/software. Some ways to shorten the file name:

Use acronyms
Use short date format
Use language code

Sequential numbering

Use leading zeros to ensure files be sorted properly. For example, PartialData_001, PartialData_002, etc. instead of PartialData_1, PartialData_2, etc..

Format for Date

Use YYYYMMDD (or YYMMDD) to make sure files are sorted in chronological order.

Case

Some file systems are case sensitive while some are not, do not use case to distinguish files.

Practices & Examples

Software and Its Engineering

Matrix organizational structure is widely used in software development, in such organizational structure,

In a team whose members are developers (programmers)
- For documents like Software Requirement Specification of which the number is fixed, use
  - ProjectName_TypeOfDocument_Authors[_ContentSummary].FileExtension
- For documents like meeting summary of which the number will increase as time flies, use
  - ProjectName_TypeOfDocument_DateCreated_Authors[_ContentSummary].FileExtension
In a team whose members are testers or quality engineers, following sounds good
- TypeOfDocument_ProjectName[_DateCreated]_Authors[_ContentSummary].FileExtension

* [_ContentSummary is optional] means it’s optional.

File is usually managed in version control system or there is a revision history table in the content, therefore, version is not included in the file name.

Prospects

Due to the limitation of the traditional file systems, files are organized in a tree structure. However, our work looks like graphs, so do our brains. One kind of research and implementation is called Semantic file system. Some modern online file systems can create tags for each file, versions can also be controlled.

We can expect better ways in document management. In any case, keep consistent and be descriptive are vital.