harvey/sys/man/1/gs

.TH GS 1
.\" This file is an edited version of /sys/src/cmd/gs/man/gs.1, to
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.de TQ
.br
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.TP \\$1
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.SH NAME 
gs \- Aladdin Ghostscript (PostScript and PDF language interpreter)
.SH SYNOPSIS
.B gs
[
.I options
] [
.I files
] ...
.br
.SH DESCRIPTION
Ghostscript is a programming language similar to Adobe Systems'
PostScript and PDF languages, which are in turn similar to Forth.
.I Gs
reads
.I files
in sequence and executes them as Ghostscript programs.
After doing this, it reads further input from the standard input.
If the
.I file
.B -
is named, however, it represents the standard input, which is read
in order and not after the files on the command line.
Each line is interpreted separately.
The `quit' command, or end-of-file, exits the interpreter.
.PP
The interpreter recognizes several switches described below, which may appear
anywhere in the command line and apply to all files thereafter.
.PP
The
.B -h
or
.B -?
options give help and list the available devices; the default is
.BR plan9 ,
which produces compressed image files suitable for viewing with
.IR page (1)
(but note that
.IR page (1)
will invoke
.I gs
automatically; see its manual).
.PP
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
.EX
	-sDEVICE=xyz
.EE
in the command line.  This switch must precede the first PostScript
file and only its first invocation has any effect.
Output devices can also be selected by the word
.B selectdevice
in the input language, or by setting the environment variable
.BR GS_DEVICE .
The order of precedence for
these alternatives, highest to lowest, is:
.EX
	selectdevice
	\f1(command line)\fP
	GS_DEVICE
	plan9
.EE
.PP
Normally, output goes
directly to a scratch file.
To send the output to a series of files
.BR foo1.xyz ,
.BR foo2.xyz ,
etc., use the switch
.EX
	-sOutputFile=foo%d.xyz
.EE
The %d may be any
.I printf
(see
.IR fprintf (2))
format specification.  Each file will receive one page of output.
If the file name begins with a pipe character,
the output will be sent as standard input to the following pipeline.
For example,
.EX
	-sOutputFile=|lp
.EE
Specifying the file
.B -
will send the files to standard output; this also requires enabling the
.B -q
option.
.SS "Initialization files"
When looking for the initialization files
.RB ( gs_*.ps ),
the files related
to fonts, or the file for the
.B run
operator, Ghostscript first looks for the file (if
it doesn't start with a slash) in the current directory, then in these
directories in the following order:
.TP
1.
Any directories specified by
.B -I
switches in the command
line (see below);
.TP
2.
Any directories specified by the
.B GS_LIB
environment variable;
.TP
3.
The directories
.BR /sys/lib/ghostscript ,
.BR /sys/lib/ghostscript/font ,
and
.BR /sys/lib/postscript/font .
.PP
The
.B GS_LIB
or
.B -I
parameters may be
a single directory or a colon-separated list.
.SS Options
.TP
.BI -- " filename arg1 ..."
Take the next argument as a file name as usual, but take all
remaining arguments (even if they have the syntactic form of switches)
and define the name ARGUMENTS in userdict (not systemdict) as an
array of those strings,
.I before
running the file.  When Ghostscript
finishes executing the file, it exits back to the shell.
.TP
.BI -D name = token
.TQ
.BI -d name = 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 white space.
.TP
.BI -D name
.TQ
.BI -d name 
Define a name in systemdict with value=null.
.TP
.BI -S name = string
.TQ
.BI -s name = string
Define a name in systemdict with a given string as value.  This is
different from
.BR  -d .
For example,
.B -dname=35
is equivalent to the
program fragment
.EX
	/name 35 def 
.EE
whereas 
.B -sname=35
is equivalent to
.EX
	/name (35) def
.EE
.TP
.B -q
Quiet startup: suppress normal startup messages, and also do the
equivalent of
.BR -dQUIET .
.TP
.BI -g number1 x number2
Equivalent to
.BI -dDEVICEWIDTH= number1 
and
.BI -dDEVICEHEIGHT= number2\f1.
This is for the benefit of devices, such as windows,
that allow width and height to be specified.
.TP
.BI -r number
.TQ
.BI -r number1 x number2
Equivalent to
.BI -dDEVICEXRESOLUTION= number1 
and
\fL-dDEVICE\%YRESOLUTION= \f2\%number2\f1.
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.
.TP
.BI -I directories
Adds the designated list of directories at the head of the
search path for library files.
.PP
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.)
.SS "Special names"
.TP
.B -dBATCH
Exit after the last file has been processed.
This is equivalent to listing
.I quit.ps
at the end of the list of files.
.TP
.B -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.
.TP
.B -dNOCACHE
Disables character caching.  Only useful for debugging.
.TP
.B -dNOBIND
Disables the `bind' operator.  Only useful for debugging.
.TP
.B -dNODISPLAY
Suppresses the normal initialization of the output device.
This may be useful when debugging.
.TP
.B -dNOPAUSE
Disables the prompt and pause at the end of each page.
This may be desirable for applications where another program
(e.g.
.IR page (1))
is
`driving' Ghostscript.
.TP
.B -dSAFER
Disables the
.B deletefile
and
.B 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.
Files in the
.B /fd
directory may still be opened for writing.
.TP
.B -dWRITESYSTEMDICT
Leaves systemdict writable.  This is necessary when running
special utility programs such as font2c and pcharstr, which must bypass
normal PostScript access protection.
.TP
.BI -sDEVICE= device
Selects an alternate initial output device, as described above.
.TP
.BI -sOutputFile= filename
Selects an alternate output file (or pipe) for the initial output
device, as described above.
.SH FILES
.TP 
.B /sys/lib/ghostscript/*
Startup-files, utilities, examples, and basic font definitions.
.TP 
.B /sys/lib/ghostscript/fonts/*
Additional font definitions.
.SH SOURCE
.B /sys/src/cmd/gs
.SH "SEE ALSO"
.IR page (1),
.IR ps2pdf (1)
.br
The Ghostscript document files in 
.B doc
and
.B man
subdirectories of the source directory.
.SH BUGS
The treatment of standard input is non-standard.