  To probe star formation processes, we present a multi-scale and
multi-wavelength investigation of the `Snake' nebula/infrared dark cloud
G11.11$-$0.12 (hereafter, G11; length $\sim$27 pc). Spitzer images hint at the
presence of sub-filaments (in absorption), and reveal four infrared-dark
hub-filament system (HFS) candidates (extent $<$ 6 pc) toward G11, where
massive clumps ($>$ 500 $M_{\odot}$) and protostars are identified. The
$^{13}$CO(2-1), C$^{18}$O(2-1), and NH$_{3}$(1,1) line data reveal a noticeable
velocity oscillation toward G11, as well as its left part (or part-A) around
V$_{lsr}$ of 31.5 km s$^{-1}$, and its right part (or part-B) around V$_{lsr}$
of 29.5 km s$^{-1}$. The common zone of these cloud components is investigated
toward the center's G11 housing one HFS. Each cloud component hosts two
sub-filaments. In comparison to part-A, more ATLASGAL clumps are observed
toward part-B. The JWST near-infrared images discover one infrared-dark HFS
candidate (extent $\sim$0.55 pc) around the massive protostar G11P1 (i.e.,
G11P1-HFS). Hence, the infrared observations reveal multiple infrared-dark HFS
candidates at multi-scale in G11. The ALMA 1.16 mm continuum map shows multiple
finger-like features (extent $\sim$3500-10000 AU) surrounding a dusty
envelope-like feature (extent $\sim$18000 AU) toward the central hub of
G11P1-HFS. Signatures of forming massive stars are found toward the center of
the envelope-like feature. The ALMA H$^{13}$CO$^{+}$ line data show two cloud
components with a velocity separation of $\sim$2 km s$^{-1}$ toward G11P1.
Overall, the collision process, the ``fray and fragment'' mechanism, and the
``global non-isotropic collapse'' scenario seem to be operational in G11.
