2.4 Command-line options

The full set of command-line options is given below:

--arch

When given as the only option, it prints the architecture identifier (see Prolog flag arch) and exits. See also -dump-runtime-variables. Also available as -arch.

--dump-runtime-variables

When given as the only option, it prints a sequence of variable settings that can be used in shell-scripts to deal with Prolog parameters. This feature is also used by swipl-ld (see section 9.5). Below is a typical example of using this feature. Also available as -dump-runtime-variables.

eval `swipl --dump-runtime-variables`
cc -I$PLBASE/include -L$PLBASE/lib/$PLARCH ...

The option can be followed by =sh to dump in POSIX shell format (default) or cmd to dump in MS-Windows cmd.exe compatible format.

--help

When given as the only option, it summarises the most important options. Also available as -h and -help.

--home=DIR

Use DIR as home directory. See section 9.6 for details.

--quiet

Set the Prolog flag verbose to silent, suppressing informational and banner messages. Also available as -q.

--nodebug

Disable debugging. See the current_prolog_flag/2 flag generate_debug_info for details.

--nosignals

Inhibit any signal handling by Prolog, a property that is sometimes desirable for embedded applications. This option sets the flag signals to false. See section 9.4.21.1 for details.

--pldoc

Start the PlDoc documentation system on a free network port and lauch the user's browser on http://localhost:\bnfmeta{port}.

-tty

Unix only. Switches controlling the terminal for allowing single-character commands to the tracer and get_single_char/1. By default manipulating the terminal is enabled unless the system detects it is not connected to a terminal or it is running as a GNU-Emacs inferior process. This flag is sometimes required for smooth interaction with other applications.

--version

When given as the only option, it summarises the version and the architecture identifier. Also available as -v.

--win_app

This option is available only in swipl-win.exe and is used for the start-menu item. If causes plwin to start in the folder ...\My Documents\Prolog or local equivalent thereof (see win_folder/2). The Prolog subdirectory is created if it does not exist.

--

Stops scanning for more arguments, so you can pass arguments for your application after this one. See current_prolog_flag/2 using the flag argv for obtaining the command-line arguments.

2.4.1 Controlling the stack-sizes

The default limit for the Prolog stacks is 128Mb on 32-bit and 256Mb on 64-bit hardware. The 128Mb limit on 32-bit system is the highest possible value and the commandline options can thus only be used to lower the limit. On 64-bit systems, the limit can both be reduced and enlarged. See section 2.19. Below are two examples, the first reducing the local stack limit to catch unbounded recursion quickly and the second using a big (32Gb) global limit, which is only possible on 64-bit hardware. Note that setting the limit using the commandline only sets a soft limit. Stack parameters can be changed (both reduced and enlarged) at any time using the predicate set_prolog_stack/2.

$ swipl -L8m
$ swipl -G32g

-Gsize[kmg]

Limit for the global stack (sometimes also called term-stack or heap). This is where compound terms and large numbers live.

-Lsize[kmg]

Limit for the local stack ((sometimes also called environment-stack). This is where environments and choice-points live.

-Tsize[kmg]

Limit for the trail stack. This is where we keep track of assignments, so we can rollback on backtracking or exceptions.

2.4.2 Running goals from the commandline

-g goal

Goal is executed just before entering the top level. Default is a predicate which prints the welcome message. The welcome message can be suppressed with --quiet, but also with -g true. goal can be a complex term. In this case quotes are normally needed to protect it from being expanded by the shell. A safe way to run a goal non-interactively is here:

% swipl <options> -g go,halt -t 'halt(1)'

-t goal

Use goal as interactive top-level instead of the default goal prolog/0. goal can be a complex term. If the top-level goal succeeds SWI-Prolog exits with status 0. If it fails the exit status is 1. If the toplevel raises an exception, this is printed as an uncaught error and the toplevel is restarted. This flag also determines the goal started by break/0 and abort/0. If you want to stop the user from entering interactive mode start the application with `-g goal' and give `halt' as top-level.

2.4.3 Compiler options

-c file ...

Compile files into an `intermediate code file'. See section 2.10.

-o output

Used in combination with -c or -b to determine output file for compilation.

-O

Optimised compilation. See current_prolog_flag/2 flag optimise for details.

-s file

Use file as a script-file. The script file is loaded after the initialisation file specified with the -f file option. Unlike -f file, using -s does not stop Prolog from loading the personal initialisation file.

-f file

Use file as initialisation file instead of the default .plrc (Unix) or pl.ini (Windows). `-f none' stops SWI-Prolog from searching for a startup file. This option can be used as an alternative to -s file that stops Prolog from loading the personal initialisation file. See also section 2.2.

-F script

Selects a startup-script from the SWI-Prolog home directory. The script-file is named <script>.rc. The default script name is deduced from the executable, taking the leading alphanumerical characters (letters, digits and underscore) from the program-name. -F none stops looking for a script. Intended for simple management of slightly different versions. One could for example write a script iso.rc and then select ISO compatibility mode using pl -F iso or make a link from iso-pl to pl.

-x bootfile

Boot from bootfile instead of the system's default boot file. A bootfile is a file resulting from a Prolog compilation using the -b or -c option or a program saved using qsave_program/[1,2].

-p alias=path1[:path2 ... ]

Define a path alias for file_search_path. alias is the name of the alias, path1 ... is a list of values for the alias. On Windows the list-separator is ;. On other systems it is :. A value is either a term of the form alias(value) or pathname. The computed aliases are added to file_search_path/2 using asserta/1, so they precede predefined values for the alias. See file_search_path/2 for details on using this file-location mechanism.

2.4.4 Maintenance options

The following options are for system maintenance. They are given for reference only.

-b initfile ...-c file ...

Boot compilation. initfile ... are compiled by the C-written bootstrap compiler, file ... by the normal Prolog compiler. System maintenance only.

-d token1,token2,...

Print debug messages for DEBUG statements tagged with one of the indicated tokens. Only has effect if the system is compiled with the -DO_DEBUG flag. System maintenance only.