html2text.1

将HTML转换为TXT文件的程序

' $Id: html2text.1,v 1.20 1999/12/20 19:40:36 arno Exp $
.TH HTML2TEXT 1 "November 1999" "Version 1.2.1"
.SH NAME
html2text \- an advanced HTML\-to\-text converter
.SH SYNOPSIS
.B html2text -help
.br
.B html2text -version
.br
.B html2text
[
.B \-unparse
|
.B \-check
] [
.B \-debug\-scanner
] [
.B \-debug\-parser
] [
.B \-rcfile
.I path
] [
.B \-style
(
.B compact
|
.B pretty
)
] [
.B \-width
.I width
] [
.B \-o
.I output-file
] [
.B \-nobs
] [
.IR input-url " ..."
]
.SH DESCRIPTION
.B Html2text
reads HTML 3.2 documents from the
.IR input-url s,
formats each into a stream of ASCII characters and writes the result to
standard output (or into
.IR output-file ,
if the
.B -o
command line option is used). It also accepts syntactically incorrect input
and attempts to interpret it "reasonably".
.PP
Documents that are specified by a URL that begins with "http:" are retrieved
with the Hypertext Transfer Protocol. URLs that begin with "file:" and URLs
that do not contain a colon specify local files. All other URLs are
invalid.
.PP
If no
.IR input-url s
are specified on the command line,
.B html2text
reads from standard input. A dash as the
.I input-url
is an alternate way to specify standard input.
.PP
The way that
.B html2text
formats the HTML documents is controlled by formatting properties read from
an RC file.
.B Html2text
attempts to read
.B $HOME/.html2textrc
(or the file specified by the
.B -rcfile
command line option); if that file cannot be read,
.B html2text
attempts to read
.BR /etc/html2textrc .
If no RC file can be read (or if the RC file does not override all formatting
properties), then "reasonable" defaults are assumed. The RC file format is
described in
.IR html2textrc(4) .
.SS OPTIONS
.TP
.B \-help
Print command line summary.
.TP
.B \-version
Print program version.
.TP
.B \-unparse
Instead of formatting the parsed document, generate HTML code. (This generated
HTML code is always syntactically correct.) If
.B html2text
has problems parsing a syntactically incorrect HTML document, this option
may help you understand what
.B html2text
thinks that the original HTML code means.
.TP
.B \-check
The HTML document(s) is/are only parsed and not processed otherwise. In this
mode of operation,
.B html2text
will report on parse errors and scan errors, which it does not in other modes
of operation. Notice that parse and scan errors are not fatal for
.IR html2text ,
but may cause mis-interpretation of the HTML code and/or portions of the
document being swallowed.
.TP
.B \-debug\-scanner
While scanning the HTML document(s),
.B html2text
reports on each lexcial token scanned.
.TP
.B \-debug\-parser
While scanning the HTML document(s),
.B html2text
reports on the tokens being shifted, rules being applied, etc.
.TP
.BI \-rcfile " path"
Attempt to read
.I path
instead of
.BR $HOME/.html2textrc .
.TP
.BR \-style " ( " compact " | " pretty " )"
Style
.B pretty
changes some of the default values of the formatting parameters documented in
.BR html2textrc(4) .
To find out which and how the formatting parameter defaults are changed, check
.BR pretty.style .
.TP
.BI \-width " width"
By default,
.B html2text
formats the HTML document(s) for a screen width of 79 characters. If your
terminal has width other than 80 characters (or if you want to get an idea how
.B html2text
deals with large tables and different terminal widths) you may want to specify a different
.IR width .
.TP
.BI \-o " output\-file"
Write the output to
.I output\-file
instead of standard output. A dash as the
.I output\-file
is an alternate way to specify the standard output.
.TP
.B \-nobs
By default,
.B html2text
renders underlined letters with sequences like "underscore-backspace-character"
and boldface letters like "character-backspace-character", which works fine
when the output is piped into
.IR more (1),
.IR less (1), 
or similar. For other applications, it may be desirable to not render
character attributes with such backspace sequences, which can be specified
with this command line option.
.SH SEE ALSO
.IR html2textrc (4),
.IR more (1),
.IR less (1)
.br
.I http://www.w3c.org
for the HTML 3.2 Reference Specification
.br
.I http://www.gmrs.de
for updates and additional information
.SH BUGS
.B Html2text
undergoes considerable effort to parse syntactically incorrect input, but is
not always as successful as other HTML processors. If you have the possibility
to correct the HTML source code, you may want to use the
.B html2text \-unparse
and
.B html2text \-check
to find out what exactly
.IR html2text 's
problem is.
.PP
.B Html2text
understands all HTML 3.2 constructs, but can render only part of them
due to the limitations of the text output format. However,
.B html2text
attempts to provide good substitutes for the elements it cannot render, e.g.
it prints
.B [image.gif]
at a position where
.B "<IMAGE SRC=image.gif>"
appears. However, there are still components and attributes that can
possibly be rendered in better ways.