Provided by: x2goserver_4.1.0.6-1.1build1_amd64 
NAME
x2gooptionsstring - X2Go Agent Options String Manipulator and Extractor
SYNOPSIS
x2gooptionsstring --help|-h|-?
x2gooptionsstring --man
x2gooptionsstring [<--mode|-m><=| >t[ransform]|-t] [--compact|-c] [--base64|-b] [--debug|-d] [--]
options_string [+]|-key[=value] ...
x2gooptionsstring <--mode|-m><=| >e[xtract]|-e [--base64|-b] [--debug|-d] [--] options_string key[=value]
...
DESCRIPTION
x2gooptionsstring is a utility for manipulating and extracting data from options strings as passed to
X2Go/NX Agent. For more information about supported options strings, refer to the OPTIONS STRINGS
section in the X2Go::Server::Agent::NX::Options documentation.
For full support of options string, which are allowed (but not recommended) to include binary data, the
special --base64|-b switch is supported. If given, all arguments other than flags must be base64-encoded
(making it possible to pass binary data via shells, for instance). The program's output, minus
potentially debugging messages, will also be base64-encoded.
Currently, two modes are supported:
Transform (default)
Transformation mode is enabled by default if no mode has been explicitly selected.
Call this program with optional flags, the options string as the first parameter and the
transformations to be carried out as additional parameters. At least one additional parameter (i.e.,
a transformation) must be provided. Transformations are described here briefly, but also in the
TRANSFORMATIONS section in the X2Go::Server::Agent::NX::Options documentation.
It can either add, remove or replace components.
To add or replace a component, pass key[=value] or +key[=value] as a parameter. The latter syntax is
useful if key starts with a dash and would therefore be interpreted as a removal operation. If the
options string does not include a key key, it will be appended to the end of the options string. If
it already exists, either with no value or a different value, the component will be replaced with the
provided value.
To fully remove a component, pass -key. To only remove it if it is set to a specific value, pass
-key=value.
Use the --compact option to minimize the original options string, removing duplicated and empty
entries.
Assuming no error happened, the resulting options string is written to stdout.
Extract
Extraction mode must be explicitly requested using the -e or <--mode|-m><=| >e[xtract] flags.
Call this program with optional flags, the options string as the first parameter and key-value pairs
to be extracted as additional parameters. At least one additional parameter (i.e., a key-value pair
to extract) must be provided.
A degenerated key-value pair without an explicit value can be used to test for the existence of a key
and extract its value at the same time.
A full, proper key-value pair can be used to test for the existence of a key-value pair exactly as
provided.
Assuming no error happened, the extracted key-value pairs will be written to stdout. Each pair will
be base64-encoded and, if multiple key-value pairs to extract have been provided, delimited via pipe
characters ("|").
Key-value pairs which haven't been found in the original options string, as well as potentially an
empty key-value pair, will be represented as empty fields.
Refer to the OPTIONS PARSING section for a description of when and how to terminate options passed to
this program.
OPTIONS
--help|-?|-h
Print a brief help message and exits.
--man Prints the manual page and exits.
--debug|-d
Enables noisy debug output.
-t Shorthand for --mode=transform.
-e Shorthand for --mode=extract.
<--mode|-m><=| >mode string
Selects a specific program mode.
Currently, the following mode strings are supported:
• transform
• extract
Mode strings can be abbreviated, as long as the abbreviation is uniquely selecting one mode
exactly.
--compact|-c
Remove duplicate and empty entries after the initial parsing. The order of arguments is
preserved in a first-seen fashion.
This option is only available in transformation mode. It will be silently ignored in extraction
mode, as compaction is a pre-requisite and done automatically during extraction.
--base64|-b
Enable a special full base64 mode.
Any binary data can be given and output by this program in this mode, even when operating on a
shell.
Input parameters must always be provided encoded in base64 form.
Likewise, the program will always output data encoded in a base64 form. Since key-value pairs
returned in extraction mode are already base64-encoded and delimited with a character that is not
legal in the base64 encoding, this flag does not modify the extraction's mode output (i.e., you
will not have to decode the output data twice).
OPTIONS PARSING
You can terminate program options parsing via a standard double-dash (--) pseudo-option. It is highly
recommended to always do so.
If you pass removal transformation operations or an extraction key-value pair starts with a dash (-),
passing the options terminator is mandatory, even if no actual options are used. Otherwise,
transformation operations or extraction key-value pairs will be interpreted as options to the program,
which will almost certainly lead to an error.
For example, passing "-clipboard" as a transformation operation without a previous options terminator
will be interpreted as the option "-c", with the rest of the string modified into "-lipboard". Since
this program does not accept an option called "-l", it will terminate with an error. Even if the program
does not terminate with an error due to an unknown option being supplied, a degradation into options is
certainly not what the original transformation operation was supposed to represent.
EXAMPLES
TRANSFORMATIONS
For an options string such as
nx/nx,clipboard=both,foo:50
calling x2gooptionsstring '--' 'nx/nx,clipboard=both,foo:50' '-clipboard' shall return
nx/nx,foo:50
while calling x2gooptionsstring '--' 'nx/nx,clipboard=both,foo:50' '-clipboard=server' shall return
nx/nx,clipboard=both,foo:50
Calling "x2gooptionsstring '--' 'nx/nx,clipboard=both,foo:50' 'bar'" shall return
nx/nx,clipboard=both,foo,bar:50
and calling x2gooptionsstring '--' 'nx/nx,clipboard=both,foo:50' '+-bar' 'foo=gulp' '-clipboard=client'
shall return
nx/nx,clipboard=both,foo=gulp,-bar:50
For an options string such as
nx/nx,clipboard=both,foo=bar,bar=baz,foo=oof:50
you can get a compacted version by cheating a bit and providing a transformation which will certainly
be a no-operation using x2gooptionsstring '-c' '--' 'nx/nx,clipboard=both,foo=bar,bar=baz,,foo=oof,:50'
'-', which shall return
nx/nx,clipboard=both,foo=oof,bar=baz:50
EXTRACTIONS
For an options string such as
nx/nx,clipboard=both,foo=bar,-=-,,bar=baz,foo=oof:50
Calling x2gooptionsstring '-e' '--' 'nx/nx,clipboard=both,foo=bar,-=-,bar=baz,foo=oof,:50' 'foo' shall
return
Zm9vPW9vZg==
while calling x2gooptionsstring '-e' '--' 'nx/nx,clipboard=both,foo=bar,-=-,bar=baz,foo=oof,:50' 'bar'
'' 'clipboard=none' '-' shall return
YmFyPWJheg==|||LT0t
AUTHOR
This manual has been written by Mihai Moldovan <ionic@ionic.de> <mailto:ionic@ionic.de> for the X2Go
project (<https://www.x2go.org>).
Version 4.1.0.6 2024-04-22 X2GOOPTIONSSTRING(1)