sqfscat

Display the contents of one or more files from a squashfs filesystem

$ sqfscat [filesystem.squashfs] [file1 file2 ...]

sqfscat SQUASHFS_IMAGE PATH_IN_IMAGE

SQUASHFS_IMAGE
    The required path to the SquashFS filesystem image file from which the content will be read.

PATH_IN_IMAGE
    The required path to the specific file within the SquashFS image whose content is to be displayed on standard output.

sqfscat is a lightweight command-line utility, typically found as part of the squashfs-tools suite. Its primary function is to display the raw content of a specific file located within a SquashFS filesystem image directly to standard output. Unlike the more comprehensive unsquashfs command, which extracts entire directories or files to the host filesystem, sqfscat provides a quick and efficient way to inspect individual files without the overhead of a full extraction operation. This makes it an invaluable tool for system administrators and developers working with embedded systems, live CDs, or other environments where SquashFS is commonly used for its excellent compression and read-only characteristics. It's particularly useful for quickly examining configuration files, scripts, or log data embedded within an image for diagnostic or debugging purposes, without modifying the host filesystem or needing to mount the SquashFS image. The command outputs the file content, similar to how cat works on regular files, and can be easily piped to other utilities for further processing.

sqfscat is not a standard, universally available Linux command like ls or cat. It is typically part of the squashfs-tools package and may need to be installed separately or might only be present in specific embedded Linux distributions or build environments. It exclusively works with SquashFS images; it cannot read other archive formats like ZIP, TAR, or ISO. The command itself does not provide options for directly redirecting output to a file or performing complex operations beyond simply printing the file's content to standard output; shell redirection must be used for such purposes.

To print the content of /etc/passwd from a SquashFS image named myrootfs.sqfs:

sqfscat myrootfs.sqfs /etc/passwd

sqfscat typically exits with a status of 0 upon successful completion. A non-zero exit status indicates an error, such as the specified SquashFS image not being found, the image being corrupted, or the requested file not existing within the image.

sqfscat is a utility derived from the broader squashfs-tools project, primarily developed by Phillip Lougher. The SquashFS filesystem itself, along with its associated tools, was created to provide a highly compressed, read-only filesystem ideal for embedded systems, live CDs, and software distribution where space and integrity are critical. sqfscat emerged as a focused tool within this suite, adhering to the Unix philosophy of providing a small, single-purpose utility. Its development is intertwined with the ongoing evolution of the SquashFS filesystem, aiming to offer convenient ways to interact with and inspect these compressed images without full extraction.

unsquashfs(1), mksquashfs(1), cat(1), mount(8) -t squashfs