Exclude or filter files using file type and regular expressions (regex)

Overview

Certain files and file types can be globally excluded from a backup without having to modify the file selection by deselecting individual files and folders. These exclusions can be added either by file type or by using regular expressions (regex). This tutorial explains how to configure your backup using both file type and regular expression exclusions.

Considerations

• Your administrator may prevent editing of file exclusions. This article assumes you have permission to create file exclusions.
• If you have an existing backup, implementing a file exclusion will delete any files in your backup archive that match that exclusion.
• CrashPlan is not responsible for data removed in this manner.

Backup sets and exclusions
Backup sets are an optional feature. If you use backup sets, special caution is needed when creating file exclusions. Specifically, file exclusions specified for any backup set impact all sets backing up to the same destination.

Example: Set A and Set B back up to an external hard drive destination. Set A has an exclusion indicating that files ending in .mp3 shouldn't back up. Even though the exclusion isn't specified for Set B, MP3s from this set will not back up to the external hard drive.

Common exclusions

Since many of the files below can be easily re-downloaded or installed, you can exclude them all together. This may decrease the initial upload duration.

• Windows executable files (.exe)
• Disc images (.iso)
• Temporary files (.tmp)
• OSX DS_Store files (.DS_Store)

Add exclusions by file type

Steps

1. Open the CrashPlan app.
2. Navigate to Backup Set Settings: 
   • Select  Settings.
   • Select Backup Sets.
3. Next to File Exclusions, select Change.
4. Enter a file extension.
   For example, to exclude your music files, enter mp3 or .mp3.
5. Click Add.
   Create additional exclusions, if desired.
6. Click Save.

Add exclusions using regular expressions

A regular expression (regex) is a search pattern that locates files and folders containing a specific sequence of characters by comparing that sequence to absolute file paths on your device. You can use the power of regular expressions to fine-tune and allow for more complex backup file exclusion rules.

Test your regular expressions
Because these types of regular expressions are often complex, it is especially important to test any regular expressions thoroughly prior to deployment in a production environment. Our technical support team can't help validate your regular expressions. Special character restrictions
Some special characters are treated differently or are restricted when used to create regular expressions:

• The following characters cannot be used in regex exclusions: <, >, and '.
• The CrashPlan app treats all file separators as forward slashes /.

Steps

1. Open the CrashPlan app.
2. Navigate to Backup Set Settings:
   • Select  Settings.
   • Select Backup Sets.
3. Next to File Exclusions, select Change.
4. Select Use Regular Expression.
   The example regex in the image below excludes any folder that starts with IMAP.
5. Click Add.
   Create additional exclusions, if desired.
6. Click Save.

Example 1 - exclude files ending with .mp3

.*\.mp3

In simple terms, this expression excludes:

• A filename of any length, made up of any character(s), that ends with .mp3

Specific components of the expression are defined as follows:

• The first dot (period) indicates the filename can contain any character, and the * indicates the filename can be any length (from a length of zero to infinity, or more accurately, up to your operating system's filename length limit).
• The backslash (\) before the second dot indicates that dot should be evaluated literally as a dot (not as a character wildcard like the dot at the beginning of the expression). You may hear this described as "the dot in .mp3 is escaped with a backslash."

Case-insensitive:

(?i).*\.mp3

Any pattern beginning with (?i) indicates a case-insensitive search, so the example above will match files that end with .mp3 and .MP3 (as well as .Mp3 and .mP3).

Example 2 - exclude files and folders starting with temp

.*/TEMP.*

This expression excludes any file or folder name that begins with TEMP. For example, the following would be excluded by this expression:

• C:\Windows\TEMP
• C:\Windows\TEMP2
• C:\Windows\TEMP.tmp
• C:\Windows\security\TEMPLATES

In the above examples, note that other directories in the \Windows and \Windows\security folders that do not begin with TEMP would still be included. However, all subdirectories, or folders within the excluded folders, would be excluded as well.

External resources

There are many fantastic regex resources on the Internet. Here are a few of our favorites:

• Regular-Expressions.info
• Regex Tutorial
• Java Regex Lesson
• Java Pattern API