GS(1)

NAME
gs - Ghostscript version 2.6 interpreter/previewer

SYNOPSIS
gs [ options ] [ files ] ...

DESCRIPTION
Ghostscript is a programming language similar to Adobe Systems' PostScript (tm) language, which is in turn similar to Forth. Gs reads files in sequence and executes them as Ghostscript programs. After doing this, it reads further input from the standard input stream (normally the keyboard). Each line is interpreted separately. To exit from the interpreter, enter the `quit' command. The interpreter also exits gracefully if it encounters end-of-file. Typing the interrupt character (e.g. Control-C) is also safe.

The interpreter recognizes several switches described below, which may appear anywhere in the command line and apply to all files thereafter.

You can get a help message by invoking Ghostscript with the -h or -? option. This message also lists the available devices.

Ghostscript may be built with multiple output devices. Ghostscript normally opens the first one and directs output to it. To use device xyz as the initial output device, include the switch
	-sDEVICE=xyz
in the command line. Note that this switch must precede the first .ps file, and only its first invocation has any effect. For example, for printer output in a normal configuration that includes an Epson printer driver, you might use the shell command
	gs -sDEVICE=epson myfile.ps
instead of just
	gs myfile.ps
Alternatively, you can type
	(epson) selectdevice
	(myfile.ps) run
All output then goes to the printer instead of the display until further notice. You can switch devices at any time by using the selectdevice procedure, e.g.,
	(vga) selectdevice
or
	(epson) selectdevice
As yet a third alternative, you can define an environment variable GS_DEVICE as the desired default device name. The order of precedence for these alternatives, highest to lowest, is:
	selectdevice
	(command line)
	GS_DEVICE
	(first device in build list)

To select the density on a printer, use
	gs -sDEVICE=<device> -r<xres>x<yres>
For example, on a 9-pin Epson-compatible printer, you can get the lowest-density (fastest) mode with
	gs -sDEVICE=epson -r60x72
and the highest-density mode with
	gs -sDEVICE=epson -r240x72.

SVGAlib OPTIONS
If you are using ghostscript to output directly to the screen (using SVGAlib extensions under Linux), then in addition to the -sDEVICE=linux flag, you may provide a resolution name or mode number with the -r<resolution> flag. The default resolution is 1024x768x256.

VIDEO MODES
These are the recognized video modes, (and mode numbers):
320x200x16     (1),  640x200x16    (2),  640x350x16    (3),
640x480x16     (4), 320x200x256    (5), 320x240x256    (6),
320x400x256    (7), 360x480x256    (8), 640x480x2      (9),
640x480x256   (10), 800x600x256   (11), 1024x768x256  (12),
320x200x32K   (13), 320x200x64K   (14), 320x200x16M   (15),
640x480x32K   (16), 640x480x64K   (17), 640x480x16M   (18),
800x600x32K   (19), 800x600x64K   (20), 800x600x16M   (21),
1024x768x32K  (22), 1024x768x64K  (23), 1024x768x16M  (24),
1280x1024x256 (25), 1280x1024x32K (26), 1280x1024x64K (27),
1280x1024x16M (28), 720x350x16    (29), 720x480x16    (30),

In addition to -r<resolution>, these flags also work with -sDEVICE=linux:

-dMAGSTEP=<value>
    Change the image size. Values 0.0 < value < 1.0 shrink the image size, while values > 1.0 expand it. The default value is 1.0.

-dXO=<value>[units]
    Specify the origin from the left side of the page. Legal units are inches (in), centimeters (cm), or percent of distance from left to right (0% - 100%). The default value is 0, and default units are inches.

-dXO=<value>[units]
    Specify the origin from the top of the page. Legal units are inches (in), centimeters (cm), or percent of distance from top to bottom (0% - 100%). The default value is 0, and the default units are inches.

PRINTER OPTIONS
If you select a printer as the output device, Ghostscript also allows you to control where the device sends its output. Normally, output goes directly to a scratch file on Unix systems. To send the output to a series of files foo1.xyz, foo2.xyz, ..., use the switch
	-sOutputFile=foo%d.xyz
The %d is a printf format specification; you can use other formats like %02d. Each file will receive one page of output. Alternatively, to send the output to a single file foo.xyz, with all the pages concatenated, use the switch
	-sOutputFile=foo.xyz

On Unix systems, you can send the output directly to a pipe. For example, to pipe the output to the command `lpr' (which, on many Unix systems, is the command that spools output for a printer), use the switch
	-sOutputFile=lpr
You can also send output to stdout for piping with the switch
	-sOutputFile=-
In this case you must also use the -q switch, to prevent Ghostscript from writing messages to stdout.

To find out what devices are available, type
	devicenames ==
after starting up Ghostscript. Alternatively, you can use the -h or -? switch in the command line; the help message also lists the available devices.

When looking for the initialization files (gs_*.ps), the files related to fonts, or the file for the `run' operator, Ghostscript first tries opening the file with the name as given (i.e., using the current working directory if none is specified). If this fails, and the file name doesn't specify an explicit directory or drive (i.e., doesn't begin with `/' on Unix systems), Ghostscript will try directories in the following order:

1.  The directory/ies specified by the -I switch(es) in the command line (see below), if any;

2.  The directory/ies specified by the GS_LIB environment variable, if any;

3.  The directory/ies specified by the GS_LIB_DEFAULT macro in the Ghostscript makefile (which has been set to "/usr/local/lib/ghostscript:/usr/local/lib/ghostscript/fonts").

Each of these (GS_LIB_DEFAULT, GS_LIB, and -I parameter) may be either a single directory, or a list of directories separated by a `:'.

X RESOURCES
Ghostscript looks for the following resources under the program name `Ghostscript':

borderWidth
    The border width in pixels (default = 1).

borderColor
    The name of the border color (default = black).

geometry
    The window size and placement, WxH+X+Y (default is NULL).

xResolution
    The number of x pixels per inch (default is computed from WidthOfScreen and WidthMMOfScreen).

yResolution
    The number of y pixels per inch (default is computed from HeightOfScreen and HeightMMOfScreen).

useBackingPixmap
    Determines whether backing store is to be used for saving display window (default = true).

See the file `use.doc' for a more complete list of resources.

To set these resources, put them in a file (such as ~/.Xresources) in the following form:

	Ghostscript*geometry:	612x792-0+0
	Ghostscript*xResolution: 72
	Ghostscript*yResolution: 72

Then load the defaults into the X server:

	% xrdb -merge ~/.Xresources

OPTIONS

-- filename arg1 ...
    Takes the next argument as a file name as usual, but takes all remaining arguments (even if they have the syntactic form of switches) and defines the name ARGUMENTS in userdict (not systemdict) as an array of those strings, before running the file. When Ghostscript finishes executing the file, it exits back to the shell.

-Dname=token
-dname=token
    Define a name in systemdict with the given definition. The token must be exactly one token (as defined by the `token' operator) and must not contain any whitespace.

-Dname
-dname
    Define a name in systemdict with value=null.

-Sname=string
-sname=string
    Define a name in systemdict with a given string as value. This is different from -d. For example, -dname=35 is equivalent to the program fragment
                /name 35 def
    whereas -s name=35 is equivalent to
                /name (35) def

-q  Quiet startup - suppress normal startup messages, and also do the equivalent of -dQUIET.

-gnumber1xnumber2
    Equivalent to -dDEVICEWIDTH=number1 and -dDEVICEHEIGHT=number2. This is for the benefit of devices (such as X11 windows) that require (or allow) width and height to be specified.

-rnumber
-rnumber1xnumber2
    Equivalent to -dDEVICEXRESOLUTION=number1 and -dDEVICEYRESOLUTION=number2. This is for the benefit of devices (such as printers) that support multiple X and Y resolutions. (If only one number is given, it is used for both X and Y resolutions.)

-Idirectories
    Adds the designated list of directories at the head of the search path for library files.

-   This is not really a switch. It indicates to Ghostscript that the standard input is coming from a file or a pipe. Ghostscript reads from stdin until reaching end-of-file, executing it like any other file, and then continues processing the command line. At the end of the command line, Ghostscript exits rather than going into its interactive mode.

Note that gs_init.ps makes systemdict read-only, so the values of names defined with -D/d/S/s cannot be changed (although, of course, they can be superseded by definitions in userdict or other dictionaries.)

SPECIAL NAMES

-dDISKFONTS
    Causes individual character outlines to be loaded from the disk the first time they are encountered. (Normally Ghostscript loads all the character outlines when it loads a font.) This may allow loading more fonts into RAM, at the expense of slower rendering.

-dNOCACHE
    Disables character caching. Only useful for debugging.

-dNOBIND
    Disables the `bind' operator. Only useful for debugging.

-dNODISPLAY
    Suppresses the normal initialization of the output device. This may be useful when debugging.

-dNOPAUSE
    Disables the prompt and pause at the end of each page. This may be desirable for applications where another program is `driving' Ghostscript.

-dNOPLATFONTS
    Disables the use of fonts supplied by the underlying platform (e.g. X Windows). This may be needed if the platform fonts look undesirably different from the scalable fonts.

-dSAFER
    Disables the deletefile and renamefile operators, and the ability to open files in any mode other than read-only. This may be desirable for spoolers or other sensitive environments.

-dWRITESYSTEMDICT
    Leaves systemdict writable. This is necessary when running special utility programs such as font2c and pcharstr, which must bypass normal PostScript access protection.

-sDEVICE=device
    Selects an alternate initial output device, as described above.

-sOutputFile=filename
    Selects an alternate output file (or pipe) for the initial output device, as described above.

FILES

/usr/local/lib/ghostscript/*
    Startup-files, utilities, and basic font definitions.

/usr/local/lib/ghostscript/fonts/*
    Additional font definitions.

/usr/local/lib/ghostscript/examples/*
    Demo Ghostscript files.

/usr/local/lib/doc/ghostscript/doc/*
    Assorted document files.

SEE ALSO
The various Ghostscript document files (above).

BUGS
See the network news group `gnu.ghostscript.bug'.