docs: Initial documentation for pySim-shell
Many bits and pieces are still missing, but it's better than nothing...
Change-Id: I19fd56aed251d064f3e5d37ffad39c1e3e39989e
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pySim-shell
===========
+
+pySim-shell is an interactive command line shell for all kind of interactions with SIM cards.
+
+The interactive shell provides command for
+
+* navigating the on-card filesystem hierarchy
+* authenticating with PINs such as ADM1
+* CHV/PIN management (VERIFY, ENABLE, DISABLE, UNBLOCK)
+* decoding of SELECT response (file control parameters)
+* reading and writing of files and records in raw, hex-encoded binary format
+* for some files where related support has been developed:
+
+ * decoded reading (display file data in JSON format)
+ * decoded writing (encode from JSON to binary format, then write)
+
+By means of using the python ``cmd2`` module, various useful features improve usability:
+
+* history of commands (persistent across restarts)
+* output re-direction to files on your computer
+* output piping through external tools like 'grep'
+* tab completion of commands and SELECT-able files/directories
+* interactive help for all commands
+
+
+cmd2 basics
+-----------
+
+FIXME
+
+
+
+ISO7816 commands
+----------------
+
+This category of commands relates to commands that originate in the ISO 7861-4 specifications,
+most of them have a 1:1 resemblance in the specification.
+
+select
+~~~~~~
+
+The ``select`` command is used to select a file, either by its FID, AID or by its symbolic name.
+
+Try ``select`` with tab-completion to get a list of all current selectable items:
+
+::
+
+ pySIM-shell (MF)> select
+ .. 2fe2 a0000000871004 EF.ARR MF
+ 2f00 3f00 ADF.ISIM EF.DIR
+ 2f05 7f10 ADF.USIM EF.ICCID
+ 2f06 7f20 DF.GSM EF.PL
+ 2f08 a0000000871002 DF.TELECOM EF.UMPC
+
+Use ``select`` with a specific FID or name to select the new file.
+
+This will
+
+* output the [JSON decoded, if possible] select response
+* change the prompt to the newly selected file
+* enable any commands specific to the newly-selected file
+
+::
+
+ pySIM-shell (MF)> select ADF.USIM
+ {
+ "file_descriptor": {
+ "shareable": true,
+ "file_type": "df",
+ "structure": "no_info_given"
+ },
+ "df_name": "A0000000871002FFFFFFFF8907090000",
+ "proprietary_info": {
+ "uicc_characteristics": "71",
+ "available_memory": 101640
+ },
+ "life_cycle_status_int": "operational_activated",
+ "security_attrib_compact": "00",
+ "pin_status_template_do": "90017083010183018183010A83010B"
+ }
+ pySIM-shell (MF/ADF.USIM)>
+
+
+
+change_chv
+~~~~~~~~~~
+
+This command allows you to change a CHV (PIN).
+
+
+disable_chv
+~~~~~~~~~~~
+
+This command allows you to disable a CHV (PIN).
+
+enable_chv
+~~~~~~~~~~
+
+This command allows you to enable a CHV (PIN).
+
+
+unblock_chv
+~~~~~~~~~~~
+
+This command allows you to unblock a CHV (PIN) using the PUK.
+
+verify_chv
+~~~~~~~~~~
+
+This command allows you to verify a CHV (PIN), which is how the specifications call
+it if you authenticate yourself with the said CHV/PIN.
+
+
+
+pySim commands
+--------------
+
+Commands in this category are pySim specific; they do not have a 1:1 correspondence to ISO 7816
+or 3GPP commands. Mostly they will operate either only on local (in-memory) state, or execute
+a complex sequence of card-commands.
+
+desc
+~~~~
+
+Display human readable file description for the currently selected file.
+
+
+dir
+~~~
+
+::
+
+ usage: dir [-h] [--fids] [--names] [--apps] [--all]
+
+ Show a listing of files available in currently selected DF or MF
+
+ optional arguments:
+ -h, --help show this help message and exit
+ --fids Show file identifiers
+ --names Show file names
+ --apps Show applications
+ --all Show all selectable identifiers and names
+
+
+export
+~~~~~~
+
+tree
+~~~~
+
+verify_adm
+~~~~~~~~~~
+
+
+
+Linear Fixed EF commands
+------------------------
+
+These commands become enabled only when your currently selected file is of *Linear Fixed EF* type.
+
+read_record
+~~~~~~~~~~~
+
+read_record_decoded
+~~~~~~~~~~~~~~~~~~~
+
+update_record
+~~~~~~~~~~~~~
+
+update_record_decoded
+~~~~~~~~~~~~~~~~~~~~~
+
+
+
+Transparent EF commands
+-----------------------
+
+These commands become enabled only when your currently selected file is of *Transparent EF* type.
+
+
+read_binary
+~~~~~~~~~~~
+
+read_binary_decoded
+~~~~~~~~~~~~~~~~~~~
+
+update_binary
+~~~~~~~~~~~~~
+
+update_binary_decoded
+~~~~~~~~~~~~~~~~~~~~~
+
+
+
+cmd2 settable parameters
+------------------------
+
+``cmd2`` has the concept of *settable parameters* which act a bit like environment variables in an OS-level
+shell: They can be read and set, and they will influence the behavior somehow.
+
+conserve_write
+~~~~~~~~~~~~~~
+
+If enabled, pySim will (when asked to write to a card) always first read the respective file/record and
+verify if the to-be-written value differs from the current on-card value. If not, the write will be skipped.
+Writes will only be performed if the new value is different from the current on-card value.
+
+If disabled, pySim will always write irrespective of the current/new value.
+
+debug
+~~~~~
+
+If enabled, full python back-traces will be displayed in case of exceptions
+
+numeric_path
+~~~~~~~~~~~~
+
+Boolean variable that determines if path (e.g. in prompt) is displayed with numeric FIDs or string names.
+
+::
+
+ pySIM-shell (MF/EF.ICCID)> set numeric_path True
+ numeric_path - was: False
+ now: True
+ pySIM-shell (3f00/2fe2)> set numeric_path False
+ numeric_path - was: True
+ now: False
+ pySIM-shell (MF/EF.ICCID)> help set