mcd

mcd [msdosdirectory]
mcd msdosdrive:
mcd msdosdrive:msdosdirectory

The mcd command is part of the mtools package, a suite of utilities designed to access and manipulate MS-DOS filesystems from a Unix or Linux environment. Its primary function is to change the current working directory within an MS-DOS filesystem, behaving analogously to the standard Unix cd command but operating on MS-DOS path conventions.

Unlike cd, mcd does not alter the Unix shell's current directory. Instead, it maintains an internal state for the mtools session, allowing subsequent mtools commands such as mdir, mcopy, or mdel to operate relative to this defined MS-DOS directory. This is particularly useful when working with floppy disks, disk images, or partitions formatted with an MS-DOS filesystem.

Users can specify paths including drive letters (e.g., A:MYDIR) and use either forward slashes or backslashes as directory separators. The command relies on mtools configuration files (like /etc/mtools.conf or ~/.mtoolsrc) to map MS-DOS drive letters to specific Unix devices or disk images, enabling seamless interaction with the target filesystem without requiring it to be mounted via the kernel's filesystem drivers. It provides a lightweight, userspace alternative for managing MS-DOS data.

mcd only affects the mtools internal working directory, not the Unix shell's current working directory.
It requires mtools to be properly configured, often via /etc/mtools.conf or ~/.mtoolsrc, to map MS-DOS drive letters to Unix devices.
MS-DOS path conventions (e.g., drive letters, backslashes) are used for arguments.
While generally reliable, interacting with complex or corrupted MS-DOS filesystems might lead to unexpected behavior.

The behavior of mcd and other mtools commands is heavily influenced by configuration files, primarily /etc/mtools.conf and ~/.mtoolsrc. These files define the mapping between MS-DOS drive letters (e.g., A:, C:) and specific Unix devices or disk image files. Correct configuration is essential for mcd to locate and operate on the intended MS-DOS filesystem.

The MTOOLSRC environment variable can be used to specify an alternative path to the mtools configuration file, overriding the default locations. This allows for flexible per-session or per-user configurations without modifying system-wide settings.

mcd typically returns an exit status of 0 upon successful execution, indicating that the directory change within the MS-DOS filesystem was successful. A non-zero exit status indicates an error, such as an invalid path, non-existent drive, or issues accessing the underlying device.

The mtools package, which includes mcd, originated in the early 1990s as a set of user-space utilities for interacting with MS-DOS filesystems from Unix-like operating systems. At the time, MS-DOS formatted floppy disks were a common medium for data exchange, and mtools provided a convenient way to access them without needing kernel-level filesystem mounting.

The initial development focused on providing a Unix-like command interface for common DOS operations. Over time, it evolved to support newer features such as VFAT (long filenames) and larger FAT filesystems. While its primary use case has diminished with the widespread adoption of modern filesystem drivers in kernels, mtools remains a valuable tool for working with legacy systems, disk images, embedded systems, or for forensic purposes where direct, unmounted access to FAT filesystems is required. Its robust design has ensured its continued inclusion in many Linux distributions.

mtools(1), mcopy(1), mdir(1), mformat(1), mdel(1), mlabel(1), cd(1)