SQFSCAT - A tool to output files to stdout

Sqfscat allows you to "cat" files to STDOUT from a Squashfs filesystem
without mounting it.  It can read all official Squashfs filesystems.

The Sqfscat usage info is:

SYNTAX: sqfscat [OPTIONS] FILESYSTEM [list of files to cat to stdout]
	-v[ersion]		print version, licence and copyright information
	-p[rocessors] <number>	use <number> processors.  By default will use
				the number of processors available
	-o[ffset] <bytes>	skip <bytes> at start of FILESYSTEM.
				Optionally a suffix of K, M or G can be given to
				specify Kbytes, Mbytes or Gbytes respectively
				(default 0 bytes).
	-ig[nore-errors]	treat errors writing files to stdout as
				non-fatal
	-st[rict-errors]	treat all errors as fatal
	-no-exit[-code]		don't set exit code (to nonzero) on non-fatal
				errors
	-da[ta-queue] <size>	set data queue to <size> Mbytes.  Default 256
				Mbytes
	-fr[ag-queue] <size>	set fragment queue to <size> Mbytes.  Default
				256 Mbytes
	-no-wild[cards]		do not use wildcard matching in filenames
	-r[egex]		treat filenames as POSIX regular expressions
				rather than use the default shell wildcard
				expansion (globbing)
	-h[elp]			output options text to stdout


The pathnames of the files to be output, like cat, can contain symbolic links,
and "." and ".." elements.

Sqfscat is a short-cut to using the equivalent Unsquashfs -cat option, i.e.
the following will behave the same:

% sqfscat image.sqfs file

% unsquashfs -cat image.sqfs file

If any of the files given on the command line does not result in a regular file,
Sqfscat will throw an error, but will continue to output the remaining
files on the command line.  This follows the behaviour of "cat", for example:

phillip@phoenix:/tmp$ sqfscat image.sqfs dir Hello_World
cat: /dir is a directory
Hello World!

phillip@phoenix:/tmp$ cat dir Hello_World
cat: dir: Is a directory
Hello World!

Sqfscat supports wildcards and it will output the contents of any file that
matches, e.g.

% sqfscat image.sqfs "*.[ch]"

Will output the contents of all the files in the root directory that match the
wildcard *.[ch], to stdout, for example hello.c, hello.h, world.c, world.h.

Note: when passing wildcarded names to Sqfscat, they should be quoted (as in
the above example), to ensure that they are not processed by the shell.

ERRORS and EXIT CODE
--------------------

If Sqfscat encounters fatal errors such as I/O error, filesystem corruption,
it will abort immediately, and return an exit code of 1.

If it skipped a file because it wasn't a regular file, or it wasn't in the
filesystem, it will return an exit code of 2.

Otherwise a success exit code of 0 will be returned.