Shelltype

Shelltype is a term used in different disciplines to describe the type or category of a shell, whether in computing as the kind of command-line interpreter, or in biology as the morphology of a mollusk's shell.

In computing, the shelltype of a system denotes the shell in use or expected by scripts. The shell is a user interface to the operating system. Common shell types include POSIX sh, Bash, Zsh, Tcsh, Ksh, and Fish. Software that runs under multiple shells may reference a variable or parameter named shelltype to tailor syntax, command options, or escaping rules. Detecting the shell type helps ensure script portability and can influence how commands are parsed or how alternatives are chosen.

In biology, shelltype describes the external shell that encases an organism such as mollusks. Shell morphology includes shape, sculpture, color, and material composition. The term is used in taxonomic descriptions and ecological studies to differentiate species or developmental stages, and to analyze evolutionary relationships. Researchers may categorize shells by type to infer ecological roles, environmental conditions, or phylogenetic connections.

In other contexts, shelltype can refer to an outer protective shell in product design or packaging, distinguishing variants with different materials or thickness. Because the phrase is not tied to a single standard definition, its meaning depends on discipline and context.

See also: shell (computing); mollusk; shell scripting.