## 5.7. Invoking the Shell

The C shell command interpreter can be invoked as follows:

>     csh  [options]  [arguments]

`csh` executes commands from a terminal or a file. Options `-n`, `-v`, and `-x` are useful when debugging scripts.

The following list details the options:

`-b`
  Allow the remaining command-line options to be interpreted as options to a specified command, rather than as options to `csh` itself.
`-c`
  Treat the first argument as a string of commands to execute. Remaining arguments are available via the `argv` array.
`-e`
  Exit if a command produces errors.
`-f`
  Fast startup; start `csh` without executing `.cshrc` or `.login`.
`-i`
  Invoke interactive shell (prompt for input).
`-n`
  Parse commands but do not execute.
`-s`
  Read commands from the standard input.
`-t`
  Exit after executing one command.
`-v`
  Display commands before executing them; expand history substitutions but don't expand other substitutions (e.g., filename, variable, and command). Same as setting `verbose`.
`-V`
  Same as `-v`, but also display `.cshrc`.
`-x`
  Display commands before executing them, but expand all substitutions. Same as setting `echo`. `-x` is often combined with `-v`.
`-X`
  Same as `-x`, but also display `.cshrc`.

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