4.2.2 Invoking Guile

Here we describe Guile's command-line processing in detail. Guile processes its arguments from left to right, recognizing the switches described below. For examples, see Scripting Examples.

-s script arg...

Read and evaluate Scheme source code from the file script, as the load function would. After loading script, exit. Any command-line arguments arg... following script become the script's arguments; the command-line function returns a list of strings of the form (script arg...).

-c expr arg...

Evaluate expr as Scheme code, and then exit. Any command-line arguments arg... following expr become command-line arguments; the command-line function returns a list of strings of the form (guile arg...), where guile is the path of the Guile executable.

-- arg...

Run interactively, prompting the user for expressions and evaluating them. Any command-line arguments arg... following the -- become command-line arguments for the interactive session; the command-line function returns a list of strings of the form (guile arg...), where guile is the path of the Guile executable.

-L directory

Add directory to the front of Guile's module load path. The given directories are searched in the order given on the command line and before any directories in the GUILE_LOAD_PATH environment variable. Paths added here are not in effect during execution of the user's .guile file.

-x extension

Add extension to the front of Guile's load extension list (see %load-extensions). The specified extensions are tried in the order given on the command line, and before the default load extensions. Extensions added here are not in effect during execution of the user's .guile file.

-l file

Load Scheme source code from file, and continue processing the command line.

-e function

Make function the entry point of the script. After loading the script file (with -s) or evaluating the expression (with -c), apply function to a list containing the program name and the command-line arguments — the list provided by the command-line function.

A -e switch can appear anywhere in the argument list, but Guile always invokes the function as the last action it performs. This is weird, but because of the way script invocation works under POSIX, the -s option must always come last in the list.

The function is most often a simple symbol that names a function that is defined in the script. It can also be of the form (@ module-name symbol) and in that case, the symbol is looked up in the module named module-name.

For compatibility with some versions of Guile 1.4, you can also use the form (symbol ...) (that is, a list of only symbols that doesn't start with @), which is equivalent to (@ (symbol ...) main), or (symbol ...) symbol (that is, a list of only symbols followed by a symbol), which is equivalent to (@ (symbol ...) symbol). We recommend to use the equivalent forms directly since they correspond to the (@ ...) read syntax that can be used in normal code, See Using Guile Modules.

See Scripting Examples.

-ds

Treat a final -s option as if it occurred at this point in the command line; load the script here.

This switch is necessary because, although the POSIX script invocation mechanism effectively requires the -s option to appear last, the programmer may well want to run the script before other actions requested on the command line. For examples, see Scripting Examples.

\

Read more command-line arguments, starting from the second line of the script file. See The Meta Switch.

--use-srfi=list

The option --use-srfi expects a comma-separated list of numbers, each representing a SRFI number to be loaded into the interpreter before starting evaluating a script file or the REPL. Additionally, the feature identifier for the loaded SRFIs is recognized by `cond-expand' when using this option.

          guile --use-srfi=8,13

--debug

Start with the debugging virtual machine engine. Using the debugging VM will enable support for VM hooks, which are needed for tracing, breakpoints, and accurate call counts when profiling. The debugging VM is slower than the regular VM, though, by about 10 percent. See VM Hooks, for more information.

By default, the debugging VM engine is only used when entering an interactive session. When executing a script with -s or -c, the normal, faster VM is used by default.

--no-debug

Do not use the debugging VM engine, even when entering an interactive session.

--listen[=p]

While this program runs, listen on a local port or a path for REPL clients. If p starts with a number, it is assumed to be a local port on which to listen. If it starts with a forward slash, it is assumed to be a path to a UNIX domain socket on which to listen.

If p is not given, the default is local port 37146. If you look at it upside down, it almost spells “Guile”. If you have netcat installed, you should be able to nc localhost 37146 and get a Guile prompt. Alternately you can fire up Emacs and connect to the process; see Using Guile in Emacs for more details.

Note that opening a port allows anyone who can connect to that port—in the TCP case, any local user—to do anything Guile can do, as the user that the Guile process is running as. Don't use --listen on multi-user machines. Of course, if you don't pass --listen to Guile, no port will be opened.

That said, --listen is great for interactive debugging and development.

-h, --help

Display help on invoking Guile, and then exit.

-v, --version

Display the current version of Guile, and then exit.