unarc

unarc [options] archive_file [files...]
unarc archive_file

-x
    Extracts files from the archive. This option is often implicit for the unarc command.

-v
    Enables verbose output, displaying the names of files as they are extracted.

-o
    Forces overwriting of existing files without prompting for confirmation.

-p
    Pipes the content of an extracted file (usually a single file) to standard output (stdout).

-d directory
    Specifies the destination directory where the extracted files should be placed. If not specified, files are extracted to the current working directory.

archive_file
    The path to the ARC archive file to be uncompressed and extracted.

files...
    Optional. A space-separated list of specific files to extract from the archive. If omitted, all files within the archive are extracted.

The unarc command is a utility designed to extract files from archives created using the ARC file format. ARC, short for ARChive, was a widely used file compression and archiving format, particularly popular on MS-DOS systems during the 1980s and early 1990s, especially within bulletin board system (BBS) communities. While largely superseded by more modern formats like ZIP, RAR, and TAR, unarc remains valuable for accessing historical or legacy data stored in ARC format. It serves as a compatibility tool on modern Linux systems, allowing users to decompress and retrieve content from these older archives. The utility typically decompresses the archived files and extracts them to the specified or current directory. Implementations of unarc on Linux are often ports of the original DOS utility or are part of broader `arc` archiving packages.

The ARC format is largely obsolete, meaning unarc is rarely found pre-installed on modern Linux distributions and might require specific package installation or compilation. It lacks advanced features like strong encryption, large file support, or solid archiving, which are common in contemporary archivers. Compatibility issues may arise with very old or non-standard ARC archives, and its command-line interface is generally simpler and less feature-rich compared to modern tools like unzip or tar.

As unarc is part of a legacy archiving system, it's not always included by default in most Linux distributions. Users typically need to install the `arc` package (e.g., `sudo apt install arc` on Debian/Ubuntu, or `sudo yum install arc` on Fedora/RHEL if available in EPEL) which often includes `unarc` as a symlink or an executable.

To extract all files from an ARC archive named my_archive.arc to the current directory:
unarc my_archive.arc

To extract a specific file named document.txt from the archive:
unarc my_archive.arc document.txt

The ARC file format was developed by Thom Henderson of System Enhancement Associates (SEA) in the early 1980s, becoming one of the first popular archive formats for personal computers. It gained significant traction through bulletin board systems (BBSs) for distributing software and files. The format's widespread use led to its being a de facto standard until the emergence of competing formats like PKZIP, which offered better compression ratios and faster performance. The unarc command on Linux systems is typically a port or a compatible re-implementation of the original DOS-era ARC extraction utility, allowing continued access to these historical archives.

arc(1), unarj(1), unzip(1), tar(1), gzip(1)