Cfpeek
1 Introduction
2 Overview of this Manual
3 Tutorial
4 Supported Configuration File Formats
5 Cfpeek Command Line Syntax
6 Exit Codes
7 Scripting
8 How to Report a Bug
Appendix A GNU Free Documentation License
Concept Index
Cfpeek
1 Introduction
2 Overview of this Manual
3 Tutorial
3.1 Basic Notions
3.2 Pathnames
3.3 Example Configuration
3.4 Listing the Entire File
3.5 Statement Lookups
3.6 Pattern Lookups
3.7 Using Various Parsers
3.8 Specifying Nodes to Output
3.9 Using Scripts
3.9.1 Example: Converter to GIT Configuration Format
4 Supported Configuration File Formats
4.1 Grecs Configuration File
4.1.1 Comments
4.1.2 Pragmatic Comments
4.1.3 Statements
4.1.4 Preprocessor
4.2 Path Configuration File
4.3 BIND Configuration File
4.4 DHCPD Configuration File
4.5 MeTA1 Configuration File
4.6 GIT Configuration File
5 Cfpeek Command Line Syntax
5.1 Patterns
5.2 Output Control
5.3 Modifiers
5.4 Scripting Options
5.5 Preprocessor Control Options
5.6 Debugging Options
5.7 Informational Options
6 Exit Codes
7 Scripting
8 How to Report a Bug
Appendix A GNU Free Documentation License
A.1 ADDENDUM: How to use this License for your documents
Concept Index
Cfpeek
******
This edition of the 'Cfpeek User Manual', last updated 6 January 2021,
documents Cfpeek Version 1.2.
1 Introduction
**************
Many programs keep their configurations in files with hierarchical
structure. Such files normally define sections, which keep logically
separated blocks of statements. These statements may in turn contain
subsections, and so on. On the lowest level of hierarchy are "simple
statements", which normally define some basic configuration settings.
Quite often a need arises to parse such files outside of their owner
program. For example, one may need to retrieve some configuration
settings to use them in a start-up script for that program, to produce a
similar configuration file with some settings changed in order to use it
on another machine, or to convert entire file into another format for
interaction with some other utility.
'Cfpeek' is a utility designed to handle any of these tasks.
2 Overview of this Manual
*************************
This book consists of the three main parts. The first part is a
tutorial, which provides a gentle (as far as possible) introduction for
those who are new to 'cfpeek'. The tutorial should help the reader to
familiarize himself with the program and to start using it. It does
not, however, cover some of the less frequently used features of
'cfpeek'.
The chapters that follow complement the tutorial. They describe
various input file formats understood by the program and summarize
command line syntax and options available to it. These two chapters can
be used as a reference by both beginners and for users familiar with the
package.
3 Tutorial
**********
The following typographic conventions are used throughout this tutorial.
In the examples, '$' represents a typical shell prompt. It precedes
lines you should type. Both command line and lines which represent the
program output are shown in 'this font'.
The Scheme code is shown as follows:
(do it)
In examples, the => symbol indicates the value of a variable or
result of a function invocation, as in:
x => 2
3.1 Basic Notions
=================
A structured configuration file contains entities of two basic types.
First of them is "simple statement". A simple statement conceptually
consists of an "identifier" (or "keyword") and a "value". Depending on
the syntactic requirements, some special token may be required between
them (such as an equals sign, for example), or at the end of the
statement. The "value", though we use the term in singular, is not
necessarily a single scalar value, it may as well be a list of values
(the exact form of that list depends on the particular syntax of the
configuration file).
Another basic entity is "compound statement", also known as "block
statement" or "section". Compound statement is used for logical
grouping of other statements. It consists of identifier, an optional
tag and a list of statements. The tag, if present, is similar to the
value in simple statements. The same notes that we made about values
apply to tags as well. Tags serve to discern between the statements
having the same identifier. The "list of statements" may include
statements of both kinds: simple as well as compound ones. Thus,
compound statements form a tree-like structure of arbitrary depth, with
simple statements as leaf nodes.
Each compound statement can have any number of "subordinate
statements", which are called its "child" statements. Each statement
(no matter simple or compound) has only one "parent statement", i.e. a
compound statement of which it is a child.
A special implicit statement, called "root statement", serves as the
parent for the statements at the topmost level of hierarchy.
3.2 Pathnames
=============
Given this hierarchical structure, each statement can be identified by
the list of keywords and values (when present) of all compound
statements that must be traversed in order to reach that statement.
Such a list, written according to a set of conventions, is called a
"full pathname" of the statement. The conventions are:
1. Pathname is written from top down.
2. An untagged statement is represented by its identifier.
3. A tagged statement is represented by its identifier, immediately
followed by an equals sign, followed by the tag.
4. Identifiers and values which contain whitespace, double quotes or
dots are enclosed in double quotes.
5. Within double quotes, a double quote is represented as '\"' and a
backslash is represented as '\\'.
6. Pathname components are separated by dots.
A pathname which begins with a component separator ('.') is called
"absolute pathname" and identifies the statement with relation to the
topmost level of hierarchy.
A pathname beginning with an identifier is called "relative" and
identifies the statement in relation to the statement represented by
that identifier.
Examples of absolute pathnames are:
.database.description
.acl=global.deny
.view=external.zone=com.type
Examples of relative pathnames are:
description
zone=com.type
3.3 Example Configuration
=========================
The following configuration file will assist us in further discussion.
Its syntax is fairly straightforward:
A simple statement is written as identifier followed value. The two
parts are separated by any amount of whitespace. Simple statements are
terminated by semicolon.
A compound statement is written as identifier followed by a list of
subordinate statements in curly braces. A tag (if present) is put
between the identifier and the opening curly brace.
These syntax conventions roughly correspond to the "Grecs
configuration format", which 'cfpeek' assumes by default (*note
grecs::).
user smith;
group mail;
pidfile "/var/run/example";
logging {
facility daemon;
tag example;
}
program a {
command "a.out";
logging {
facility local0;
tag a;
}
}
program b {
command "b.out";
wait yes;
pidfile /var/run/b.pid;
}
Example 3.1: Sample configuration file
3.4 Listing the Entire File
===========================
The only argument 'cfpeek' requires is the name of the file to parse.
If no other arguments are given, it produces on the standard output a
listing of that file in "pathname-value" form. Each simple statement in
the input file is represented by a single line in the output listing.
The line consists of two main parts: the full pathname of that statement
and its value. The two parts are separated by a colon and space
character. For example:
$ cfpeek sample.conf
.user: smith
.group: mail
.pidfile: /var/run/example
.logging.facility: daemon
.logging.tag: example
.program="a".command: a.out
.program="a".logging.facility: local0
.program="a".logging.tag: a
.program="b".command: b.out
.program="b".wait: yes
.program="b".pidfile: /var/run/b.pid
This output can be customized via the '--format' ('-H') command line
option. This option takes a list of "output flags", each of which
modifies some aspect of the output. Most output flags are boolean, i.e.
they enable or disable the given feature. To disable the feature, the
flag must be prefixed with 'no'.
To list only the pathnames, use
$ cfpeek --format=path sample.conf
.user
.group
.pidfile
.logging.facility
.logging.tag
.program="a".command
.program="a".logging.facility
.program="a".logging.tag
.program="b".command
.program="b".wait
.program="b".pidfile
The default output is equivalent to '--format=path,value,descend'.
The flags 'path' and 'value' mean to print the pathname of the
statement and its value. The 'descend' flag affects the output of
compound nodes. If this flag is set and a node matching the key is a
compound node, 'cfpeek' will output this node and all nodes below it
(i.e. its descendant nodes). The 'descend' flag is meaningful only if
at least one lookup key is supplied.
You can also use '--format' to change the default component
delimiter. For example, to use slash to delimit components:
$ cfpeek --format=delim=/ sample.conf
/user: smith
/group: mail
/pidfile: /var/run/example
/logging/facility: daemon
/logging/tag: example
/program="a"/command: a.out
/program="a"/logging/facility: local0
/program="a"/logging/tag: a
/program="b"/command: b.out
/program="b"/wait: yes
/program="b"/pidfile: /var/run/b.pid
3.5 Statement Lookups
=====================
When given more than one argument, 'cfpeek' treats the rest of arguments
as "search keys". It then searches for statements with pathnames
matching each of the keys and outputs them. A key can be either a
pathname, or a pattern.
The following command looks for the 'pidfile' statement at the
topmost level of hierarchy and prints it:
$ cfpeek sample.conf .pidfile
.pidfile: /var/run/example
As you see, it uses the same output format as with full listings. If
you wish to change it, use the '--format' option, introduced in the
previous section. For example, to retrieve only the value:
$ cfpeek --format=value sample.conf .pidfile
/var/run/example
This approach is quite common when 'cfpeek' is used in shell scripts.
It will be illustrated in more detail below.
If a key is not found, 'cfpeek' prints a message on the standard
error and starts searching for the next key (if any). When all keys are
exhausted, the program exits with status 1 to indicate that some of them
have not been found. To suppress the diagnostics output, use the
'--quiet' ('-q') option.
To illustrate all this, the following example shows how to use
'cfpeek' in a start-up script to check whether a program has already
been started and to bring it down, if requested:
#! /bin/sh
pidfile=`cfpeek -q --format=value sample.conf .pidfile`
if test -f $pidfile; then
pid=`head -1 $pidfile`
else
pid=
fi
case $1 in
start) if test -n "$pid"; then
echo >&2 "the program is already running"
else
# start the program
sample-start
fi
;;
status) if test -n "$pid"; then
echo "program is running at pid $pid"
else
echo "program is not running"
fi
;;
stop) test -n "$pid" && kill -TERM $pid
;;
esac
3.6 Pattern Lookups
===================
Apart from literal pathname, a "pathname pattern" is allowed as a key.
A pattern can contain "wildcards" in place of path components. Two
wildcards are defined: '*' and '%'. A '%' matches any single keyword:
$ cfpeek sample.conf .%.pidfile
.program="b".pidfile: /var/run/b.pid
A '*' wildcard matches zero or more keywords appearing in its place:
$ cfpeek sample.conf .*.pidfile
.pidfile: /var/run/example
.program="b".pidfile: /var/run/b.pid
In addition to these wildcards, tags in a pattern can contain
traditional globbing patterns, as described in *note match filename or
pathname: (fnmatch(3))fnmatch.
$ cfpeek sample.conf '.program=[ab].pidfile'
.program="b".pidfile: /var/run/b.pid
Pattern lookups can be disabled using the '--literal' ('-L') command
line option. There may be two reasons for doing so. First, literal
lookups are somewhat faster, so if you don't need pattern matching using
'--literal' can save you a couple of CPU cycles. Secondly, if any of
your identifiers contain '*' or '%' characters, you will have to use
'--literal' to prevent them from being treated as wildcards.
3.7 Using Various Parsers
=========================
'Cfpeek' can handle input files in various formats. The default one is
'Grecs' format, introduced in previous sections. To process input files
of another format, specify the "parser" to use via the '--parser' ('-p')
command line option. The argument to this option is one of: 'grecs',
'bind', 'path', 'meta1' or 'git'. *Note Formats::, for a detailed
description of each of these formats.
For example, to select zone statements from the '/etc/named.conf'
file:
$ cfpeek --parser=bind /etc/named.conf '.*.zone'
3.8 Specifying Nodes to Output
==============================
Sometimes you may need to see not the node which matched the search key,
but its parent or other ancestor node. Consider, for example, the
following task: select from the '/etc/named.conf' file the names of all
zones for which this nameserver is a master. To do so, you will need to
find all 'zone.type' statements with the value 'master', ascend to the
parent node and print its value.
'Cfpeek' provides several special formatting flags to that effect:
'up', 'down', 'parent', 'child' and 'sibling'. They are called
"relative movement" flags, because they select another node in the tree,
relative to the position of the current node.
The 'up' flag takes an integer number as its argument. It instructs
'cfpeek' to ascend that many parent nodes before actually printing the
node. For example, '--format=up=1' means "ascend to the parent of the
matched node and print it". This is exactly what we need to solve the
above task, since the 'type' statement is a child of a 'zone' statement.
Thus, the solution is:
cfpeek --format=up=1,nodescend,value --parser=bind \
/etc/named.conf .*.type=master
The 'value' flag indicates that we want on output only values, without
the corresponding pathnames. The 'nodescend' flag tells 'cfpeek' to not
descend into compound statements when outputting them. It is necessary
since we want only values of all relevant 'zone' statements, no their
subordinate statements.
A counterpart of this flag is 'down=N' flag, which descends N levels
of hierarchy.
The 'parent' flag acts in the similar manner, but it identifies the
ancestor by its keyword, instead of the relative nesting level. The
statement
--format=parent=zone
tells 'cfpeek', after finding a matching node, to ascend until a node
with the identifier 'zone' is found, and then print this node.
The 'child=ID' statement does the opposite of 'parent': it locates a
child of the current node which has the identifier ID.
Similarly, the 'sibling' keyword instructs 'cfpeek' to find first
sibling of the current node wich has the given identifier. For example,
to find names of the zone files for all master nodes in the 'named.conf'
file:
cfpeek --parser bind --format=sibling=file,value /etc/named.conf \
'.*.zone.type=master'
A 'file' statement is located on the same nesting level as 'type',
for example:
zone "example.net" {
type master;
file "db.example.net";
};
Thus, the above command first locates the 'type' statement, then
searches on the same nesting level for a 'file' statement, and finally
prints its value.
3.9 Using Scripts
=================
'Cfpeek' offers a scripting facility, which can be used to easily extend
its functionality beyond the basic operations, described in previous
chapters. Scripts must be written in Scheme, using 'Guile', the "GNU's
Ubiquitous Intelligent Language for Extensions". For information about
the language, refer to *note (r5rs)Top::. For a detailed description of
Guile and its features, see *note Overview: (guile)Top.
This section assumes that the reader has sufficient knowledge about
this programming language.
The scripting facility is enabled by the use of the '--expression'
('-e') of '--file' ('-f' command line options. The '--expression'
('-e') option takes as its argument a Scheme expression, which will be
executed for each statement matching the supplied keys (or for each
statement in the tree, if no keys were supplied). The expression can
obtain information about the statement from the global variable 'node',
which represents a node in the parse tree describing this statement.
The node contains complete information about the statement, including
its location in the source file, its type and neighbor nodes, etc. A
number of functions is provided to retrieve that information from the
node. These functions are discussed in detail in *note Scripting::.
Let's start from the simplest example. The following command prints
all nodes in the file:
$ cfpeek --expression='(display node)(newline)' sample.conf
#<node .user: "smith">
#<node .group: "mail">
#<node .pidfile: "/var/run/example">
#<node .logging.facility: "daemon">
#<node .logging.tag: "example">
#<node .program="a".command: "a.out">
#<node .program="a".logging.facility: "local0">
#<node .program="a".logging.tag: "a">
#<node .program="b".command: "b.out">
#<node .program="b".wait: "yes">
#<node .program="b".pidfile: "/var/run/b.pid">
The format shown in this example is the default Scheme representation
for nodes. You can use accessor functions to format the output to your
liking. For instance, the function 'grecs-node-locus' returns the
location of the node in the input file. The returned value is a cons,
with the file name as its car and the line number as its cdr. Thus, you
can print statement locations with the following command:
cfpeek --expr='(let ((loc grecs-node-locus))
(format #t "~A:~A~%"
(car loc) (cdr loc)))' \
sample.conf
Complex expressions are cumbersome to type in the command line,
therefore the '--file' ('-f') option is provided. This option takes the
name of the script file as its argument. This file must define the
function named 'cfpeek' which takes a node as its argument. The script
file is then loaded and the 'cfpeek' function is called for each
matching node.
Now, if we put the expression used in the previous example in a
script file (e.g. 'locus.scm'):
(define (cfpeek node)
(let ((loc grecs-node-locus))
(format #t "~A:~A~%" (car loc) (cdr loc))))
then the example can be rewritten as:
$ cfpeek -f locus.scm sample.conf
When both '--file' and '--expression' options are used in the same
invocation, the 'cfpeek' function is not invoked by default. In fact,
it even does not need to be defined. When used this way, 'cfpeek' first
loads the requested script file, and then applies the expression to each
matching node, the same way it always does when '--expression' is
supplied. It is the responsibility of the expression itself to call any
function or functions defined in the file. This way of invoking
'cfpeek' is useful for supplying additional parameters to the script.
For example:
$ cfpeek -f script.scm -e '(process-node node #t)' input.conf
It is supposed that the function 'process-node' is defined somewhere
in 'script.scm' and takes two arguments: a node and a boolean.
The '--init=EXPR' ('-i EXPR') option provides an initialization
expression EXPR. This expression is evaluated once, after loading the
script file, if one is specified, and before starting the main loop.
Similarly, the option '--done=EXPR' ('-d EXPR') introduces a Scheme
expression to be evaluated at the end of the run, after all nodes have
been processed.
3.9.1 Example: Converter to GIT Configuration Format
----------------------------------------------------
Here is a more practical example of Scheme scripting. This script
converts entire parse tree into a GIT configuration file format. The
format itself is described in *note git::.
The script traverses entire tree itself, so it must be called only
once, for the root node of the parse tree. The root node is denoted by
a single dot, so the invocation syntax is:
cfpeek -f togit.scm sample.conf .
Traversal is performed by the main function, 'cfpeek', using the
'grecs-node-next' and 'grecs-node-down' functions. The
'grecs-node-next' function returns a node which follows its argument at
the same nesting level. For example, if N is the very first node in our
sample parse tree, then:
n => #<node .user: "smith">
(grecs-node-next n) => #<node .group: "mail">
Similarly, the 'grecs-node-down' function returns the first
subordinate node of its argument. For example:
n => #<node .logging>
(grecs-node-down n) => #<node .logging.facility: "daemon">
Both functions return '#f' if there are no next or subordinate node,
correspondingly.
The 'grecs-node-type' function is used to determine how to handle
that particular node. It returns a "type" of the node given to it as
argument. The type is an integer constant, with the following possible
values:
Type The node is
--------------------------------------------------------------------------
grecs-node-root the root (topmost) node
grecs-node-stmt a simple statement
grecs-node-block a compound (block) statement
The 'print-section' function prints a GIT section header
corresponding to its node. It ascends the parent node chain to find the
topmost node and prints the traversed nodes in the correct order.
To summarize, here is the listing of the 'togit.scm' script:
(define (print-section node delim)
"Print a Git section header for the given node.
End it with delim.
The function recursively calls itself until the topmost
node is reached.
"
(cond
((grecs-node-up? node)
;; Ascend to the parent node
(print-section (grecs-node-up node) #\space)
;; Print its identifier, ...
(display (grecs-node-ident node))
(if (grecs-node-has-value? node)
;; ... value,
(begin
(display " ")
(display (grecs-node-value node))))
;; ... and delimiter
(display delim))
(else ;; mark the root node
(display "[")))) ;; with a [
(define (cfpeek node)
"Main entry point. Calls itself recursively to descend
into subordinate nodes and to iterate over nodes on the
same nesting level (tail recursion)."
(let loop ((node node))
(if node
(let ((type (grecs-node-type node)))
(cond
((= type grecs-node-root)
(let ((dn (grecs-node-down node)))
;; Each statement in a Git config file must
;; belong to a section. If the first node
;; is not a block statement, provide the
;; default [core] section:
(if (not (= (grecs-node-type dn)
grecs-node-block))
(display "[core]\n"))
;; Continue from the first node
(loop dn)))
((= type grecs-node-block)
;; print the section header
(print-section node #\])
(newline)
;; descend into subnodes
(loop (grecs-node-down node))
;; continue from the next node
(loop (grecs-node-next node)))
((= type grecs-node-stmt)
;; print the simple statement
(display #\tab)
(display (grecs-node-ident node))
(display " = ")
(display (grecs-node-value node))
(newline)
;; continue from the next node
(loop (grecs-node-next node))))))))
If run on our sample configuration file, it produces:
$ cfpeek -f togit.scm sample.conf .
[core]
user = smith
group = mail
pidfile = /var/run/example
[logging]
facility = daemon
tag = example
[program a]
command = a.out
[program a logging]
facility = local0
tag = a
[program b]
command = b.out
wait = yes
pidfile = /var/run/b.pid
4 Supported Configuration File Formats
**************************************
'Cfpeek' is able to handle input files in several formats. The
supported formats differ mostly in syntax. This chapter describes them
in detail. If you know of any free software which uses a structured
configuration file not understood by 'cfpeek', please let us know (*note
Reporting Bugs::).
4.1 Grecs Configuration File
============================
This is the default input format. It is used, e.g., by GNU Dico(1), GNU
Mailutils(2), GNU Radius(3), Mailfromd(4) and others.
The configuration file consists of statements and comments.
There are three classes of lexical tokens: keywords, values, and
separators. Blanks, tabs, newlines and comments, collectively called
"white space" are ignored except as they serve to separate tokens. Some
white space is required to separate otherwise adjacent keywords and
values.
---------- Footnotes ----------
(1) *Note GNU Dico: (dico)Top.
(2) *Note GNU Mailutils: (mailutils)Top.
(3) *Note GNU Radius: (radius)Top.
(4) *Note Mailfromd: (mailfromd)Top.
4.1.1 Comments
--------------
"Comments" may appear anywhere where white space may appear in the
configuration file. There are two kinds of comments: single-line and
multi-line comments. "Single-line" comments start with '#' or '//' and
continue to the end of the line:
# This is a comment
// This too is a comment
"Multi-line" or "C-style" comments start with the two characters '/*'
(slash, star) and continue until the first occurrence of '*/' (star,
slash).
Multi-line comments cannot be nested. However, single-line comments
may well appear within multi-line ones.
4.1.2 Pragmatic Comments
------------------------
Pragmatic comments are similar to usual single-line comments, except
that they cause some changes in the way the configuration is parsed.
Pragmatic comments begin with a '#' sign and end with the next physical
newline character.
'#include <FILE>'
'#include FILE'
Include the contents of the file FILE. There are three possible
use cases.
If FILE is an absolute file name, the named file is included. An
error message will be issued if it does not exist.
If FILE contains wildcard characters ('*', '[', ']' or '?'), it is
interpreted as shell globbing pattern and all files matching that
pattern are included, in lexicographical order. If no files match
the pattern, the statement is silently ignored.
Otherwise, the form with angle brackets searches for file in the
"include search path", while the second one looks for it in the
current working directory first, and, if not found there, in the
include search path. If the file is not found, an error message
will be issued.
The default include search path is:
1. 'PREFIX/share/PROGRAM-NAME/1.2/include'
2. 'PREFIX/share/PROGRAM-NAME/include'
where PREFIX is the installation prefix.
'#include_once <FILE>'
'#include_once FILE'
Same as '#include', except that, if the FILE has already been
included, it will not be included again.
'#line NUM'
'#line NUM "FILE"'
This line causes the parser to believe, for purposes of error
diagnostics, that the line number of the next source line is given
by NUM and the current input file is named by FILE. If the latter
is absent, the remembered file name does not change.
'# NUM "FILE"'
This is a special form of '#line' statement, understood for
compatibility with the C preprocessor.
In fact, these statements provide a rudimentary preprocessing
features. For more sophisticated ways to modify configuration before
parsing, see *note Preprocessor::.
4.1.3 Statements
----------------
A "simple statement" consists of a keyword and value separated by any
amount of whitespace. Simple statement is terminated with a semicolon
(';').
The following is a simple statement:
standalone yes;
pidfile /var/run/slb.pid;
A "keyword" begins with a letter and may contain letters, decimal
digits, underscores ('_') and dashes ('-'). Examples of keywords are:
'expression', 'output-file'.
A "value" can be one of the following:
number
A number is a sequence of decimal digits.
boolean
A boolean value is one of the following: 'yes', 'true', 't' or '1',
meaning "true", and 'no', 'false', 'nil', '0' meaning "false".
unquoted string
An unquoted string may contain letters, digits, and any of the
following characters: '_', '-', '.', '/', '@', '*', ':'.
quoted string
A quoted string is any sequence of characters enclosed in
double-quotes ('"'). A backslash appearing within a quoted string
introduces an "escape sequence", which is replaced with a single
character according to the following rules:
Sequence Replaced with
\a Audible bell character (ASCII 7)
\b Backspace character (ASCII 8)
\f Form-feed character (ASCII 12)
\n Newline character (ASCII 10)
\r Carriage return character (ASCII
13)
\t Horizontal tabulation character
(ASCII 9)
\v Vertical tabulation character
(ASCII 11)
\\ A single backslash ('\')
\" A double-quote.
Table 4.1: Backslash escapes
In addition, the sequence '\NEWLINE' is removed from the string.
This allows to split long strings over several physical lines,
e.g.:
"a long string may be\
split over several lines"
If the character following a backslash is not one of those
specified above, the backslash is ignored and a warning is issued.
Here-document
A "here-document" is a special construct that allows to introduce
strings of text containing embedded newlines.
The '<<WORD' construct instructs the parser to read all the
following lines up to the line containing only WORD, with possible
trailing blanks. Any lines thus read are concatenated together
into a single string. For example:
<<EOT
A multiline
string
EOT
The body of a here-document is interpreted the same way as a
double-quoted string, unless WORD is preceded by a backslash (e.g.
'<<\EOT') or enclosed in double-quotes, in which case the text is
read as is, without interpretation of escape sequences.
If WORD is prefixed with '-' (a dash), then all leading tab
characters are stripped from input lines and the line containing
WORD. Furthermore, if '-' is followed by a single space, all
leading whitespace is stripped from them. This allows to indent
here-documents in a natural fashion. For example:
<<- TEXT
The leading whitespace will be
ignored when reading these lines.
TEXT
It is important that the terminating delimiter be the only token on
its line. The only exception to this rule is allowed if a
here-document appears as the last element of a statement. In this
case a semicolon can be placed on the same line with its
terminating delimiter, as in:
help-text <<-EOT
A sample help text.
EOT;
list
A "list" is a comma-separated list of values. Lists are enclosed
in parentheses. The following example shows a statement whose
value is a list of strings:
alias (test,null);
In any case where a list is appropriate, a single value is allowed
without being a member of a list: it is equivalent to a list with a
single member. This means that, e.g.
alias test;
is equivalent to
alias (test);
A "block statement" introduces a logical group of statements. It
consists of a keyword, followed by an optional value, and a sequence of
statements enclosed in curly braces, as shown in the example below:
server srv1 {
host 10.0.0.1;
community "foo";
}
The closing curly brace may be followed by a semicolon, although this
is not required.
4.1.4 Preprocessor
------------------
Before actual parsing, the configuration file is preprocessed. The
built-in preprocessor handles only file inclusion and '#line' statements
(*note Pragmatic Comments::), while the rest of traditional
preprocessing facilities, such as macro expansion, is supported via
'm4', which serves as external preprocessor.
The detailed description of 'm4' facilities lies far beyond the scope
of this document. You will find a complete user manual in *note GNU M4
manual: (m4)Top. For the rest of this subsection we assume the reader
is sufficiently acquainted with 'm4' macro processor.
The external preprocessor is invoked with '-s' flag, which instructs
it to include line synchronization information in its output. This
information is then used by the parser to display meaningful diagnostic.
An initial set of macro definitions is supplied by the 'pp-setup'
file, located in 'PREFIX/share/PROGRAM-NAME/1.2/include' directory.
The default 'pp-setup' file renames all 'm4' built-in macro names so
they all start with the prefix 'm4_'. This is similar to GNU m4
'--prefix-builtin' option, but has an advantage that it works with
non-GNU 'm4' implementations as well.
4.2 Path Configuration File
===========================
A "pathname configuration file" format corresponds exactly to the
default output format of 'cfpeek', i.e. it lists each terminal keyword
as its full pathname, followed by a semicolon, a single space and its
value, as in the example below:
.user: "smith"
.group: "mail"
.pidfile: "/var/run/example"
.logging.facility: "daemon"
.logging.tag: "example"
.program="a".command: "a.out"
.program="a".logging.facility: "local0"
.program="a".logging.tag: "a"
.program="b".command: "b.out"
.program="b".wait: "yes"
.program="b".pidfile: "/var/run/b.pid"
This format is similar to the one used in X-resources.
4.3 BIND Configuration File
===========================
This is the format used by the ISC BIND configuration files. In
general, it is pretty similar to the 'Grecs', except that it does not
support neither here-documents, not list values. Some of its features,
such as 'acls' and 'allow-*' lists do resemble lists, but are not them
in reality. Such "suspicious" statements are represented as simple
statements. For example, the following statement in 'named.conf':
allow-transfer {
allow-dns;
!10.10.10.1;
10.10.10.0/8;
};
.allow-transfer.allow-dns:
.allow-transfer.!: "10.10.10.1"
.allow-transfer."10.10.10.0/8":
Another exception is the 'controls' statement, which doesn't fall
well into the general syntax of BIND configuration file. Therefore a
special rule is applied to handle it. In the effect, the following
statement:
controls {
inet 127.0.0.1 port 953
allow { 127.0.0.1; 127.0.0.2; } keys { "rndc-key"; };
};
produces
.controls: (inet, 127.0.0.1, port, 953, allow, \
(127.0.0.1, 127.0.0.2), keys, (rndc-key))
4.4 DHCPD Configuration File
============================
This is the format used by the ISC DHCPD configuration files
('/etc/dhcpd.conf' and any files it might include). It is very similar
to 'Bind', with some minor differences:
* Block statements do not end with a semicolon.
* Tags or values can contain lists of quoted strings delimited by
commas.
4.5 MeTA1 Configuration File
============================
This type of configuration file is used by "MeTA1", an advanced MTA
program. See <http://www.meta1.org> for details about the program and
its configuration.
The syntax is similar to both 'Grecs' and 'Bind' in that it uses
curly braces to delimit subordinate statements. The syntax for strings
is similar to 'Grecs' (*note quoted string: Statements.). As in
'Grecs', adjacent quoted strings are concatenated to produce a single
string.
The principal syntactic differences are:
* Only '#' comments are understood.
* An equal sign is required between identifier and value in simple
statements, e.g.:
log_level = 12;
* List values are enclosed in curly braces.
* Here-document is not supported.
4.6 GIT Configuration File
==========================
This is the format used by Git (<http://git-scm.com>). It is described
in detail in *Note CONFIGURATION FILE: (git-config(1))git-config.
The syntax is line-oriented. Comments are introduced by '#' or ';'
character and extend up to the next physical newline. Statements are
delimited by newlines.
The syntax for simple statement is:
IDENT = VALUE
Compound statements or "sections" begin with a "section header", i.e.
a full pathname of that section using single space as a separator and
enclosed in a pair of square brackets. Any identifier in the path which
contains whitespace characters must be quoted using double quotes.
Double quotes and backslashes appearing in a section name must be
escaped as '\"' and '\\' correspondingly. For example:
[section "subsection name" subsubsection]
An alternative syntax for section headers is a full pathname of the
section using single dot as a separator and enclosed in a pair of square
brackets. When this syntax is used, whitespace is not allowed in
section names:
[section.subsection.subsubsection]
A section begins with the section headers and continues until the
start of next section or end of file, whichever occurs first.
Simple statements must occur only within a section. In other words,
each non-empty configuration file must contain at least one section.
String values may be entirely or partially enclosed in double quotes,
similarly to shell syntax. The following escape sequences are
recognized within a value:
Sequence Stands for
--------------------------------------------------------------------------
'\"' '"'
'\\' '\'
'\b' Backspace (ASCII 8)
'\t' Horizontal tab (ASCII 9)
'\n' Newline (ASCII 10)
A backslash immediately preceding a newline indicates line
continuation. Both characters are removed and the remaining characters
are joined with line that follows.
5 Cfpeek Command Line Syntax
****************************
The format of 'cfpeek' invocation is:
cfpeek OPTIONS FILE [KEYS]
where OPTIONS are command line options, FILE is the configuration file
to operate upon, and optional KEYS are pathnames of the keywords to
locate in that configuration file.
If KEYS are supplied, 'cfpeek', for each KEY, looks up in the parse
tree for any nodes matching the key and prints them on the standard
output. An error message is displayed for any key which has no matching
statements in the input file. In this case, program continues iterating
over the rest of KEYS. When the list is exhausted, 'cfpeek' will exit
with the status 1 (*note Exit Codes::).
If either '-f' ('--file') or '-e' ('--expression') has been given, a
Scheme expression or the default 'cfpeek' function is evaluated for each
matching node. If '-e' ('--expression') is given, the node is passed to
it in the global 'node' variable. Otherwise, if '-f' ('--file') is
given, the node is passed as argument to 'cfpeek' function.
If both '--file=SCRIPT' and '--expression=EXPRESSION' options are
given, the script file SCRIPT is loaded first, and the EXPRESSION is
evaluated for each matching node. The expression can then refer to any
variables and call any functions defined in the SCRIPT.
If no keys are supplied, the program operates as if given a single
'.*' key (*note Patterns::), which matches any node in the parse tree
(i.e., it iterates over the entire parse tree).
5.1 Patterns
============
By default 'cfpeek' treats keys as "wildcard patterns". When matching
statement identifiers (keywords), two characters have special meaning:
'%' and '*'.
A '%' character in place of an identifier matches any single keyword.
Thus, e.g.:
cfpeek file.conf .%.bar.baz
will match '.foo.bar.baz', '.qux.bar.baz', but will not match '.bar.baz'
or '.x.y.bar.baz'.
A single '*' character in place of a keyword matches zero or more
keywords appearing in its place, so that:
cfpeek file.conf .*.bar.baz
The tags in block statement are matched using the traditional
globbing patterns. *Note match filename or pathname:
(fnmatch(3))fnmatch.
For example, this:
cfpeek file.conf .*.program="mh-*"
will match any 'program' block statement whose tag begins with 'mh-'.
5.2 Output Control
==================
'-H FLAGS'
'--format=FLAGS'
Set output format flags. The argument is a comma-separated list of
format flags and "relative movement" options. Relative movement
options select another node, relative to the one found. They are:
'parent=ID'
Find a parent of the matching node, which has ID as its
identifier.
'child=ID'
Find a child of the matching node, which has ID as its
identifier.
'child=ID'
Find a sibling of the matching node, which has ID as its
identifier.
'up=N'
Ascend N parent nodes and print the node at which the ascent
stopped.
'descend=N'
Descend N child nodes.
Any number of relative movement options can be specified. They are
executed in the order of their appearance in the '--format'
statement. For example, '--format=up=2,sibling=foo,child=bar'
means: ascend two levels of hierarchy, find a node named 'foo',
look for a node named 'bar' among the children of that node and
print the result.
If evaluation of the relative movement options results in an empty
node (e.g. the 'up' option attempts to go past the root of the
tree), nothing is output.
The 'delim' flag controls how keyword paths is printed:
'delim=CHAR'
Sets path component delimiter, instead of the default '.'.
The following flags control the amount of information printed for
each node. These are boolean flags: when prefixed with 'no' they
have the meaning opposite to the described.
'locus'
Print source location of each configuration statement. A
location is printed as the file name, followed by a semicolon,
followed by the line number and another semicolon. Locations
are separated from the rest of output by a single space
character.
'path'
Print statement paths.
'value'
Print statement values.
'quote'
Always quote string values.
'never-quote'
Never quote string values.
'quote-hex'
Print non-printable characters as C hex escapes. This option
is ignored if 'noquote' is set.
'descend'
Descend into subnodes. Set default options.
The default format options are: 'path,value,quote,descend'.
'-q'
'--quiet'
Suppress error diagnostics. *Note quiet: Lookups.
5.3 Modifiers
=============
The following options modify the way 'cfpeek' processes the parse tree
and search keys.
'-L'
'--literal'
Use literal matching, instead of pattern matching. *Note
literal::.
'-S'
'--sort'
Before further processing, sort parse tree lexicographically in
ascending order.
'-m'
'--matches=NUMBER'
Output at most NUMBER matches for each key.
'-p'
'--parser=TYPE'
Set parser type for the input file. The argument is one of:
'grecs', 'path', 'meta1', 'bind', 'dhcpd', and 'git'
(case-insensitive). *Note Formats::, for a description of each
type.
'-r'
'--reduce'
Reduce the parse tree, so that each keyword occurs no more than
once at each tree level.
'-s PATH=VAL'
'--set=PATH=VAL'
Set a keyword PATH to VALUE. The produced parse tree node will be
processed as usual.
5.4 Scripting Options
=====================
The following options control the scripting facility of 'cfpeek'.
'-e EXPRESSION'
'--expression=EXPRESSION'
Apply this expression to each node found. The global variable
'node' is set to the node being processed before evaluating. When
used together with '--file=SCRIPT', the expression can refer to any
variables and call any functions defined in the SCRIPT file.
'-f FILE'
'--file=FILE'
Load the script FILE. Unless '--expression' is also given, the
script must define the function named 'cfpeek' which takes a node
as its only argument. This function will be called for each
matching node.
If '--expression' is given, this behavior is suppressed. It is
then the responsibility of the expression to call any functions
defined in this file.
'-i EXPR'
'--init=EXPR'
The '--init=EXPR' ('-i EXPR') option provides an initialization
expression EXPR. This expression is evaluated once, after loading
the script file, if one is specified, and before starting the main
loop.
'-l SCRIPT-LANGUAGE'
'--lang=SCRIPT-LANGUAGE'
Select scripting language to use. This option is reserved for
further use. As of version 1.2, the only possible value for
SCRIPT-LANGUAGE is 'scheme'.
5.5 Preprocessor Control Options
================================
The options described below control the preprocessor facility. They are
meaningful only for 'GRECS' and 'BIND' configuration files.
Preprocessor is not used for another configuration file formats.
'-DNAME[=VALUE]'
'--define=NAME[=VALUE]'
Define the preprocessor symbol NAME as having VALUE, or empty.
*Note Preprocessor::.
'-I DIR'
'--include-directory=DIR'
Add DIR to include search path.
*Note #include: Pragmatic Comments.
'-N'
'--no-preprocessor'
Disable preprocessor. *note Preprocessor::.
'-P COMMAND'
'--preprocessor=COMMAND'
Use COMMAND instead of the default preprocessor. *note
Preprocessor::.
5.6 Debugging Options
=====================
The options below enable trace output which helps understand how
configuration parser works. They are mainly useful for 'cfpeek'
developers.
'-X'
'--debug-lexer'
Trace configuration file lexer.
'-x'
'--debug-parser'
Trace configuration file parser.
5.7 Informational Options
=========================
'--help'
'-h'
Print a concise usage summary and exit.
'--usage'
Print a summary of command line syntax and exit.
'--version'
'-v'
Print the program version and exit.
6 Exit Codes
************
When cfpeek terminates, it reports the result of its invocation via its
exit code. Exit code of 0 indicates normal termination. Exit code 1
indicates that not all search keys has been found. Exit codes greater
than 1 indicate various error conditions. The exact cause of failure is
reported on the standard error.
The exit codes are as follows:
2
Error parsing the input file.
3
Script failure.
64
The command was used incorrectly, e.g., with the wrong number of
arguments, a bad option, a bad syntax in a parameter, or whatever.
69
The requested script file does not exist, contains syntax errors,
or cannot be parsed for whatever other reason.
70
An internal software error has occurred. Please, report it, along
with any error diagnostics produced by the program, if you ever
stumble upon this error code. *Note Reporting Bugs::, for detailed
instructions.
78
The script file parses correctly, but does not define all the
symbols required by 'cfpeek'.
7 Scripting
***********
This chapter describes the Scheme functions available for use in
'cfpeek' scripts. For an introduction to 'cfpeek' scripting facility,
see *note Scripts::.
-- Scheme Procedure: grecs-node? obj
Returns '#t' if OBJ is a valid tree node.
-- Scheme Procedure: grecs-node-root node
Returns the topmost node that can be traced up from NODE.
-- Scheme Procedure: grecs-node-head node
Returns the first node having the same parent and located on the
same nesting level as NODE. I.e. the following always holds true:
(let ((head (grecs-node-head node)))
(and
(eq? (grecs-node-up node) (grecs-node-up head))
(not (grecs-node-prev? head))))
-- Scheme Procedure: grecs-node-tail node
Returns the last node having the same parent and located on the
same nesting level as node. In other words, the following relation
is always '#t':
(let ((tail (grecs-node-tail node)))
(and
(eq? (grecs-node-up node) (grecs-node-up tail))
(not (grecs-node-next? tail))))
-- Scheme Procedure: grecs-node-up? node
Return true if NODE has a parent node.
-- Scheme Procedure: grecs-node-up node
Return parent node of NODE.
-- Scheme Procedure: grecs-node-down? node
Returns '#t' if NODE has child nodes.
-- Scheme Procedure: grecs-node-down node
Returns the first child node of NODE.
-- Scheme Procedure: grecs-node-next? node
Returns '#t' if NODE is followed by another node on the same
nesting level.
-- Scheme Procedure: grecs-node-next node
Returns the node following NODE on the same nesting level.
-- Scheme Procedure: grecs-node-prev? node
Returns '#t' if NODE is preceded by another node on the same
nesting level.
-- Scheme Procedure: grecs-node-prev node
Returns the node preceding NODE on the same nesting level.
-- Scheme Procedure: grecs-node-ident node
Returns identifier of the node NODE.
-- Scheme Procedure: grecs-node-ident-locus node [full]
Returns locus of the NODE's identifier. Returned value is a cons
whose parts depend on FULL, which is a boolean value. If FULL is
'#f', which is the default, then returned value is a cons:
(FILE-NAME . LINE-NUMBER)
Oherwise, if FULL is '#t', the function returns the locations where
the node begins and ends:
((BEG-FILE-NAME BEG-LINE BEG-COLUMN) .
(END-FILE-NAME END-LINE END-COLUMN))
-- Scheme Procedure: grecs-node-path-list node
Returns the full path to the node, converted to a list. Each list
element corresponds to a subnode identifier. A subnode which has a
tag is represented by a cons, whose car contains the subnode
identifier, and cdr its value. For example, the following path:
.foo.bar=x.baz
is represented as
'("foo" ("bar" . "x") "baz")
-- Scheme Procedure: grecs-node-path node [delim]
Returns the full path to the NODE (a string).
-- Scheme Procedure: grecs-node-type node
Returns the type of the node. The following constants are defined:
grecs-node-root
The node is a root node. The following is always '#t':
(and (= (grecs-node-type node) grecs-node-root)
(not (grecs-node-up? node))
(not (grecs-node-prev? node)))
grecs-node-stmt
The node is a simple statement. The following is always '#t':
(and (= (grecs-node-type node) grecs-node-stmt)
(not (grecs-node-down? node)))
grecs-node-block
The node is a block statement.
-- Scheme Procedure: grecs-node-has-value? node
Returns '#t' if NODE has a value.
-- Scheme Procedure: grecs-node-value node
Returns the value of NODE.
-- Scheme Procedure: grecs-node-value-locus node [full]
Returns locus of the NODE's value. Returned value is a cons whose
parts depend on FULL, which is a boolean value. If FULL is '#f',
which is the default, then returned value is a cons:
(FILE-NAME . LINE-NUMBER)
Oherwise, if FULL is '#t', the function returns the locations where
the node begins and ends:
((BEG-FILE-NAME BEG-LINE BEG-COLUMN) .
(END-FILE-NAME END-LINE END-COLUMN))
-- Scheme Procedure: grecs-node-locus node [full]
Returns source location of the NODE. Returned value is a cons
whose parts depend on FULL, which is a boolean value. If FULL is
'#f', which is the default, then returned value is a cons:
(FILE-NAME . LINE-NUMBER)
Oherwise, if FULL is '#t', the function returns the locations where
the node begins and ends:
((BEG-FILE-NAME BEG-LINE BEG-COLUMN) .
(END-FILE-NAME END-LINE END-COLUMN))
-- Scheme Procedure: grecs-find-node node path
Returns the first node whose path is PATH. Starts search from
NODE.
-- Scheme Procedure: grecs-match-first node pattern
Returns the first node whose path matches PATTERN. The search is
started from NODE.
-- Scheme Procedure: grecs-match-next node
NODE must be a node returned by a previous call to
'grecs-match-first' or 'grecs-match-next'. The function returns
next node matching the initial pattern, or '#f' if no more matches
are found. For example, the following code iterates over all nodes
matching PATTERN:
(define (iterate-nodes root pattern thunk)
(do ((node (grecs-match-first root pattern)
(grecs-match-next node)))
((not node))
(thunk node)))
8 How to Report a Bug
*********************
Please, report bugs and suggestions to <bug-cfpeek@gnu.org.ua>.
You hit a bug if at least one of the conditions below is met:
* 'cfpeek' terminates on signal 11 (SIGSEGV) or 6 (SIGABRT).
* 'cfpeek' terminates with exit code 70 (internal software error).
* The program fails to do its job as described in this manual.
If you think you've found a bug, please be sure to include maximum
information available to reliably reproduce it, or at least to analyze
it. The information needed is:
* Version of the package you are using.
* Command line options and input file (or files) used.
* Conditions under which the bug appears.
Any errors, typos or omissions found in this manual also qualify as
bugs. Please report them, if you happen to find any.
Appendix A GNU Free Documentation License
*****************************************
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document "free" in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book. We
recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it can
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"Document", below, refers to any such manual or work. Any member
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A "Modified Version" of the Document means any work containing the
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The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow the
conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the title
equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as
long as they preserve the title of the Document and satisfy these
conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with
each Opaque copy a computer-network location from which the general
network-using public has access to download using public-standard
network protocols a complete Transparent copy of the Document, free
of added material. If you use the latter option, you must take
reasonably prudent steps, when you begin distribution of Opaque
copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or
through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies,
to give them a chance to provide you with an updated version of the
Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with the
Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever
possesses a copy of it. In addition, you must do these things in
the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of previous
versions (which should, if there were any, be listed in the
History section of the Document). You may use the same title
as a previous version if the original publisher of that
version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the
Title Page. If there is no section Entitled "History" in the
Document, create one stating the title, year, authors, and
publisher of the Document as given on its Title Page, then add
an item describing the Modified Version as stated in the
previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in the
"History" section. You may omit a network location for a work
that was published at least four years before the Document
itself, or if the original publisher of the version it refers
to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the section
all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered
in their text and in their titles. Section numbers or the
equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option designate
some or all of these sections as invariant. To do this, add their
titles to the list of Invariant Sections in the Modified Version's
license notice. These titles must be distinct from any other
section titles.
You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of
the list of Cover Texts in the Modified Version. Only one passage
of Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document
already includes a cover text for the same cover, previously added
by you or by arrangement made by the same entity you are acting on
behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added
the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination all
of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the documents
in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of
this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled "Acknowledgements",
"Dedications", or "History", the requirement (section 4) to
Preserve its Title (section 1) will typically require changing the
actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document
except as expressly provided for under this License. Any other
attempt to copy, modify, sublicense or distribute the Document is
void, and will automatically terminate your rights under this
License. However, parties who have received copies, or rights,
from you under this License will not have their licenses terminated
so long as such parties remain in full compliance.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of
the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
<http://www.gnu.org/copyleft/>.
Each version of the License is given a distinguishing version
number. If the Document specifies that a particular numbered
version of this License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that specified version or of any later version that has been
published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may
choose any version ever published (not as a draft) by the Free
Software Foundation.
A.1 ADDENDUM: How to use this License for your documents
========================================================
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:
Copyright (C) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with
the Front-Cover Texts being LIST, and with the Back-Cover Texts
being LIST.
If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.
Concept Index
*************
This is a general index of all issues discussed in this manual
* Menu:
* #include: Pragmatic Comments. (line 745)
* #include_once: Pragmatic Comments. (line 771)
* #line: Pragmatic Comments. (line 776)
* %, a wildcard: Patterns. (line 1131)
* %, a wildcard <1>: Pattern Lookups. (line 355)
* *, a wildcard: Patterns. (line 1139)
* *, a wildcard <1>: Pattern Lookups. (line 359)
* --file and --expression used together: Scripts. (line 534)
* --file and --expression used together <1>: Invocation. (line 1115)
* absolute pathname: Pathnames. (line 159)
* bind configuration format: bind. (line 972)
* block statement: Basic Notions. (line 121)
* block statement <1>: Statements. (line 909)
* boolean value: Statements. (line 813)
* cfpeek, Scheme function: Scripting Options. (line 1279)
* child: Nodes to Print. (line 440)
* child <1>: Output Control. (line 1167)
* child statement: Basic Notions. (line 132)
* Comments in a configuration file: Comments. (line 722)
* comments, pragmatic: Pragmatic Comments. (line 740)
* compound statement: Basic Notions. (line 121)
* configuration file statements: Statements. (line 794)
* d, -d short option, described: Scripts. (line 553)
* D, -D short option, summary: Preprocessor Control Options.
(line 1308)
* debug-lexer, --debug-lexer option, summary: Debugging Options.
(line 1335)
* debug-parser, --debug-parser option, summary: Debugging Options.
(line 1339)
* default: Output Control. (line 1220)
* define, --define option, summary: Preprocessor Control Options.
(line 1308)
* delim: Output Control. (line 1195)
* delim, format flag: Listing. (line 275)
* descend: Listing. (line 268)
* descend <1>: Output Control. (line 1218)
* dhcpd configuration format: dhcpd. (line 1007)
* done, --done option, described: Scripts. (line 553)
* down: Nodes to Print. (line 428)
* down <1>: Output Control. (line 1179)
* e, -e short option, introduced: Scripts. (line 476)
* e, -e short option, summary: Scripting Options. (line 1270)
* escape sequence: Statements. (line 821)
* exit code: Exit Codes. (line 1360)
* expression, --expression option, introduced: Scripts. (line 476)
* expression, --expression option, summary: Scripting Options.
(line 1270)
* f, -f short option, introduced: Scripts. (line 516)
* f, -f short option, summary: Scripting Options. (line 1277)
* FDL, GNU Free Documentation License: Copying This Manual.
(line 1568)
* file, --file option, introduced: Scripts. (line 516)
* file, --file option, summary: Scripting Options. (line 1277)
* format, --format option, in statement look-ups: Lookups. (line 305)
* format, --format option, introduced: Listing. (line 245)
* format, --format option, summary: Output Control. (line 1157)
* format, input: Formats. (line 689)
* GIT Configuration Converter: Scripting Example. (line 560)
* git configuration format: git. (line 1042)
* globbing pattern: Pattern Lookups. (line 368)
* globbing patterns: Patterns. (line 1144)
* grecs configuration format: grecs. (line 698)
* grecs-find-node: Scripting. (line 1522)
* grecs-match-first: Scripting. (line 1526)
* grecs-match-next: Scripting. (line 1530)
* grecs-node-block: Scripting. (line 1489)
* grecs-node-down: Scripting. (line 1428)
* grecs-node-down <1>: Scripting Example. (line 570)
* grecs-node-down?: Scripting. (line 1425)
* grecs-node-has-value?: Scripting. (line 1492)
* grecs-node-head: Scripting. (line 1400)
* grecs-node-ident: Scripting. (line 1445)
* grecs-node-ident-locus: Scripting. (line 1448)
* grecs-node-locus: Scripting. (line 1510)
* grecs-node-next: Scripting. (line 1435)
* grecs-node-next <1>: Scripting Example. (line 570)
* grecs-node-next?: Scripting. (line 1431)
* grecs-node-path: Scripting. (line 1472)
* grecs-node-path-list: Scripting. (line 1460)
* grecs-node-prev: Scripting. (line 1442)
* grecs-node-prev?: Scripting. (line 1438)
* grecs-node-root: Scripting. (line 1397)
* grecs-node-root <1>: Scripting. (line 1478)
* grecs-node-stmt: Scripting. (line 1484)
* grecs-node-tail: Scripting. (line 1409)
* grecs-node-type: Scripting Example. (line 588)
* grecs-node-type <1>: Scripting. (line 1475)
* grecs-node-up: Scripting. (line 1422)
* grecs-node-up?: Scripting. (line 1419)
* grecs-node-value: Scripting. (line 1495)
* grecs-node-value-locus: Scripting. (line 1498)
* grecs-node?: Scripting. (line 1394)
* Guile: Scripts. (line 466)
* H, -H short option, in statement look-ups: Lookups. (line 305)
* H, -H short option, introduced: Listing. (line 245)
* H, -H short option, summary: Output Control. (line 1157)
* h, -h short option, summary: Informational Options.
(line 1346)
* help, --help option, summary: Informational Options.
(line 1346)
* here-document: Statements. (line 853)
* i, -i short option, described: Scripts. (line 549)
* i, -i short option, summary: Scripting Options. (line 1288)
* I, -I short option, summary: Preprocessor Control Options.
(line 1313)
* identifier: Basic Notions. (line 111)
* include-directory, --include-directory option, summary: Preprocessor Control Options.
(line 1313)
* init, --init option, described: Scripts. (line 549)
* init, --init option, summary: Scripting Options. (line 1288)
* input formats: Parsers. (line 385)
* input formats <1>: Formats. (line 689)
* input parsers: Parsers. (line 385)
* keyword: Basic Notions. (line 111)
* L, -L short option, described: Pattern Lookups. (line 375)
* L, -L short option, summary: Modifiers. (line 1234)
* l, -l short option, summary: Scripting Options. (line 1295)
* lang, --lang option, summary: Scripting Options. (line 1295)
* list: Statements. (line 893)
* literal, --literal option, described: Pattern Lookups. (line 375)
* literal, --literal option, summary: Modifiers. (line 1234)
* locus: Output Control. (line 1202)
* look-up key: Lookups. (line 294)
* m, -m short option, summary: Modifiers. (line 1244)
* m4: Preprocessor. (line 924)
* matches, --matches option, summary: Modifiers. (line 1244)
* MeTA1 configuration format: meta1. (line 1018)
* multi-line comments: Comments. (line 730)
* N, -N short option, summary: Preprocessor Control Options.
(line 1319)
* never-quote: Output Control. (line 1213)
* no-preprocessor, --no-preprocessor option, summary: Preprocessor Control Options.
(line 1319)
* node: Scripting Options. (line 1272)
* node, Guile variable: Scripts. (line 476)
* nodefault: Output Control. (line 1220)
* nodescend: Output Control. (line 1218)
* nolocus: Output Control. (line 1202)
* nonever-quote: Output Control. (line 1213)
* nopath: Output Control. (line 1207)
* noquote: Output Control. (line 1211)
* noquote-hex: Output Control. (line 1215)
* novalue: Output Control. (line 1209)
* p, -p short option, described: Parsers. (line 385)
* p, -p short option, summary: Modifiers. (line 1248)
* P, -P short option, summary: Preprocessor Control Options.
(line 1323)
* parent: Nodes to Print. (line 431)
* parent <1>: Output Control. (line 1163)
* parent statement: Basic Notions. (line 132)
* parser, --parser option, described: Parsers. (line 385)
* parser, --parser option, summary: Modifiers. (line 1248)
* path: Output Control. (line 1207)
* path configuration format: path. (line 950)
* path, format flag: Listing. (line 251)
* pathname: Pathnames. (line 143)
* pathname, absolute: Pathnames. (line 159)
* pathname, relative: Pathnames. (line 163)
* pathname-value listing: Listing. (line 224)
* pattern: Pattern Lookups. (line 355)
* pattern <1>: Patterns. (line 1127)
* pp-setup: Preprocessor. (line 935)
* pragmatic comments: Pragmatic Comments. (line 740)
* preprocessor: Preprocessor. (line 924)
* preprocessor control: Preprocessor Control Options.
(line 1304)
* preprocessor, --preprocessor option, summary: Preprocessor Control Options.
(line 1323)
* q, -q short option, described: Lookups. (line 315)
* q, -q short option, summary: Output Control. (line 1224)
* quiet, --quiet option, described: Lookups. (line 315)
* quiet, --quiet option, summary: Output Control. (line 1224)
* quote: Output Control. (line 1211)
* quote-hex: Output Control. (line 1215)
* quoted string: Statements. (line 821)
* r, -r short option, summary: Modifiers. (line 1255)
* reduce, --reduce option, summary: Modifiers. (line 1255)
* relative pathname: Pathnames. (line 163)
* root statement: Basic Notions. (line 137)
* S, -S short option, summary: Modifiers. (line 1239)
* s, -s short option, summary: Modifiers. (line 1260)
* Scheme: Scripts. (line 466)
* scripts: Scripts. (line 466)
* search key: Lookups. (line 294)
* section: Basic Notions. (line 121)
* set, --set option, summary: Modifiers. (line 1260)
* sibling: Nodes to Print. (line 443)
* sibling <1>: Output Control. (line 1171)
* simple statement: Basic Notions. (line 111)
* simple statements: Intro. (line 59)
* simple statements <1>: Statements. (line 794)
* single-line comments: Comments. (line 722)
* sort, --sort option, summary: Modifiers. (line 1239)
* start-up scripts: Lookups. (line 321)
* statement look-up: Lookups. (line 294)
* statement, block: Statements. (line 909)
* statement, simple: Statements. (line 794)
* statement, subordinate: Basic Notions. (line 132)
* statements, configuration file: Statements. (line 794)
* string, quoted: Statements. (line 821)
* string, unquoted: Statements. (line 817)
* structured configuration file: Intro. (line 59)
* subordinate statement: Basic Notions. (line 132)
* substatement: Basic Notions. (line 132)
* tag, in a compound statement: Basic Notions. (line 121)
* up: Nodes to Print. (line 412)
* up <1>: Output Control. (line 1175)
* usage, --usage option, summary: Informational Options.
(line 1350)
* V, -V short option, summary: Informational Options.
(line 1353)
* value: Listing. (line 268)
* value <1>: Basic Notions. (line 111)
* value <2>: Output Control. (line 1209)
* version, --version option, summary: Informational Options.
(line 1353)
* wildcards: Patterns. (line 1127)
* X, -X short option, summary: Debugging Options. (line 1335)
* x, -x short option, summary: Debugging Options. (line 1339)
* X-resources: path. (line 950)