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Linux / Unix Command: ghostscript
Command Library

NAME

gs - Ghostscript (PostScript and PDF language interpreter and previewer)  

SYNOPSIS

gs [ options ] [ files ] ... (Unix, VMS)
gswin32 [ options ] [ files ] ... (MS Windows)
gswin32c [ options ] [ files ] ... (MS Windows)
gs386 [ options ] [ files ] ... (DOS for PC)
gsos2 [ options ] [ files ] ... (OS/2)  

DESCRIPTION

The gs (gswin32, gswin32c, gs386, gsos2) command invokes Ghostscript, an interpreter of Adobe Systems' PostScript(tm) and Portable Document Format (PDF) languages. 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), interpreting each line separately. The interpreter quits gracefully when it encounters the "quit" command (either in a file or from the keyboard), at end-of-file, or at an interrupt signal (such as Control-C at the keyboard).

The interpreter recognizes several switches described below, which may appear anywhere in the command line and apply to all files thereafter. Invoking Ghostscript with the -h or -? switch produces a message which shows several useful switches, all the devices known to that executable, and the search path for fonts; on Unix it also shows the location of detailed documentation.

Ghostscript may be built able to use many different output devices. To see which devices your executable can use, run "gs -h". Unless you specify a particular device, Ghostscript normally opens the first one of those and directs output to it, so if the first one in the list is the one you want to use, just issue the command

        gs myfile.ps

You can also check the set of available devices from within Ghostscript: invoke Ghostscript and type

        devicenames ==

but the first device on the resulting list may not be the default device you determine with "gs -h". To specify "AbcXyz" as the initial output device, include the switch

        -sDEVICE=AbcXyz

For example, for output to an Epson printer you might use the command

        gs -sDEVICE=epson myfile.ps

The "-sDEVICE=" switch must precede the first mention of a file to print, and only the switch's first use has any effect. Alternatively, in Ghostscript you can type

        (epson) selectdevice
        (myfile.ps) run

All output then goes to the printer until you select another device with the "selectdevice" procedure in the PostScript program stream, for example

        (vga) selectdevice
or
        (x11) selectdevice

Finally, you can specify a default device in the environment variable GS_DEVICE. The order of precedence for these alternatives from highest to lowest (Ghostscript uses the device defined highest in the list) is:

        selectdevice
        (command line)
        GS_DEVICE
        (first device in build list)

Some printers can print at different resolutions (densities). To specify the resolution on such a printer, use the "-r" switch:

        gs -sDEVICE=<device> -r<xres>x<yres>

For example, on a 9-pin Epson-compatible printer, you get the lowest-density (fastest) mode with

        gs -sDEVICE=epson -r60x72

and the highest-density (best output quality) mode with

        gs -sDEVICE=epson -r240x72.

If you select a printer as the output device, Ghostscript also allows you to choose where Ghostscript sends the output -- on Unix systems, usually to a temporary file. To send the output to a file "foo.xyz", use the switch

        -sOutputFile=foo.xyz

You might want to print each page separately. To do this, send the output to a series of files "foo1.xyz, foo2.xyz, ..." using the "-sOutputFile=" switch with "%d" in a filename template:

        -sOutputFile=foo%d.xyz

Each resulting file receives one page of output, and the files are numbered in sequence. "%d" is a printf format specification; you can also use a variant like "%02d".

On Unix systems you can also send output to a pipe. For example, to pipe output to the "lpr" command (which, on many Unix systems, directs it to a printer), use the switch

        -sOutputFile=\|lpr

You can also send output to standard output for piping with the switch

        -sOutputFile=-

In this case you must also use the -q switch, to prevent Ghostscript from writing messages to standard output.

To select a specific paper size, use the command line switch

        -sPAPERSIZE=a_known_paper_size

for instance

        -sPAPERSIZE=a4
or
        -sPAPERSIZE=legal

At this time, the known paper sizes, defined in the initialization file "gs_statd.ps", are:

PAPERSIZEX inchesY inchesX cmY cm

a033.055646.777883.9611118.816
a123.388933.055659.407883.9611
a216.527823.388941.980659.4078
a311.694416.527829.703941.9806
a48.2638911.694420.990329.7039
a55.847228.2638914.851920.9903
a64.1255.8472210.477514.8519
a72.916674.1257.4083310.4775
a82.055562.916675.221117.40833
a91.458332.055563.704175.22111
a101.027781.458332.610563.70417
b039.388955.6667100.048141.393
b127.833339.388970.6967100.048
b219.694427.833350.023970.6967
b313.916719.694435.348350.0239
b49.8472213.916725.011935.3483
b56.958339.8472217.674225.0119
archA91222.8630.48
archB121830.4845.72
archC182445.7260.96
archD243660.9691.44
archE364891.44121.92
flsa8.51321.5933.02
flse8.51321.5933.02
halfletter5.58.513.9721.59
note7.51019.0525.4
letter8.51121.5927.94
legal8.51421.5935.56
11x17111727.9443.18
ledger171143.1827.94

Note that the B paper sizes are ISO sizes: for information about using JIS B sizes, see Use.htm.

Ghostscript can do many things other than print or view PostScript and PDF files. For example, if you want to know the bounding box of a PostScript (or EPS) file, Ghostscript provides a special "device" that just prints out this information:

        gs -sDEVICE=bbox myfile.ps

For example, using one of the example files distributed with Ghostscript,

        gs -sDEVICE=bbox golfer.ps

prints out

        %%BoundingBox: 0 25 583 732
        %%HiResBoundingBox: 0.808497 25.009496 582.994503 731.809445
 

INITIALIZATION FILES

When looking for the initialization files "gs_*.ps", the files related to fonts, or the file for the "run" operator, Ghostscript first tries to open the file with the name as given, using the current working directory if no directory is specified. If this fails, and the file name doesn't specify an explicit directory or drive (for instance, doesn't contain "/" on Unix systems or "\" on DOS systems), Ghostscript tries directories in this order:
1.
the directories specified by the -I switches in the command line (see below), if any;
2.
the directories specified by the GS_LIB environment variable, if any;
3.
the directories specified by the GS_LIB_DEFAULT macro in the Ghostscript makefile when the executable was built. When gs is built on Unix, GS_LIB_DEFAULT is usually "/usr/local/share/ghostscript/#.##:/usr/local/share/ghostscript/fonts" where "#.##" represents the Ghostscript version number.

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

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 usage document for a more complete list of resources. To set these resources on Unix, put them in a file such as "~/.Xresources" in the following form:

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

Then merge these resources into the X server's resource database:

        % xrdb -merge ~/.Xresources
 

SWITCHES

-- 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 may contain no 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 -sname=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, but indicates to Ghostscript that standard input is coming from a file or a pipe and not interactively from the command line. Ghostscript reads from standard input until it reaches end-of-file, executing it like any other file, and then continues with processing the command line. When the command line has been entirely processed, Ghostscript exits rather than going into its interactive mode.

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

SPECIAL NAMES

-dSAFER
Disables the "deletefile" and "renamefile" operators and the ability to open files in any mode other than read-only. This is desirable for spoolers or any other environments where a malicious or badly written PostScript program must be prevented from changing important files.
-dBATCH
Causes Ghostscript to exit after processing all files named on the command line, rather than prompting for further PostScript commands.
-dNOPAUSE
Disables the prompt and pause at the end of each page. This may be desirable in converting documents or for applications where another program is driving Ghostscript.
-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.
-dNODISPLAY
Suppresses the normal initialization of the output device. This may be useful when debugging.
-dNOCACHE
Disables character caching. Useful only for debugging.
-dNOBIND
Disables the "bind" operator. Useful only for debugging.
-dNOPLATFONTS
Disables the use of fonts supplied by the underlying platform (for instance X Windows). This may be needed if the platform fonts look undesirably different from the scalable fonts.
-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.
-dWRITESYSTEMDICT
Leaves "systemdict" writable. This is necessary when running special utility programs such as font2c and pcharstr, which must bypass normal PostScript access protection.

 

SEE ALSO

The various Ghostscript document files (above), especially Use.htm.  

Important: Use the man command (% man) to see how a command is used on your particular computer.

>> Linux/Unix Command Library

>> Shell Command Library

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