Force Unrar to Use a Specific Temp Directory

When extracting large RAR archives on systems with limited space on the default root or drive partition, redirecting temporary files is essential to avoid out-of-disk-space errors. This guide explains how to force the unrar command-line utility to use a designated temporary or working directory instead of the system default, ensuring seamless extraction and better disk management.

Using the -w Switch

The most direct way to specify a temporary directory in unrar is with the -w<path> switch. This command tells the extraction tool to assign a custom work directory for unpacking intermediate files.

The syntax requires appending your target directory directly to the flag:

unrar x -w/path/to/custom_temp archive.rar

On Windows, the command structure remains identical with Windows paths:

unrar x -wC:\CustomTemp archive.rar

Ensure there is no space between the -w flag and the path, and verify that the target directory already exists and has the appropriate write permissions.

Using the TMPDIR Environment Variable (Linux/macOS)

If you are using a build of unrar that relies on standard system libraries to generate temporary files, setting the temporary environment variable for the execution session will redirect temporary data.

Run the extraction with TMPDIR prepended to the command:

TMPDIR=/path/to/custom_temp unrar x archive.rar

This overrides the default /tmp location for the duration of that specific command without altering system-wide environment variables.

Using the TEMP Environment Variable (Windows)

On Windows, command-line utilities frequently pull their temporary workspace location from the TEMP or TMP environment variables. You can redirect this in a Command Prompt session:

set TEMP=D:\CustomTemp
set TMP=D:\CustomTemp
unrar x archive.rar

This ensures that any operations requiring temporary staging utilize the designated drive rather than filling up your primary C: drive.