`test': Check file types and compare values
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`test' returns a status of 0 (true) or 1 (false) depending on the
evaluation of the conditional expression EXPR. Each part of the
expression must be a separate argument.
`test' has file status checks, string operators, and numeric
comparison operators.
Because most shells have a built-in command by the same name, using
the unadorned command name in a script or interactively may get you
different functionality than that described here.
Besides the options below, `test' accepts a lone `--help' or
`--version'. Note:Common options. A single non-option argument is
also allowed: `test' returns true if the argument is not null.