# code.mindmeldr.com /graphterm

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# Using GraphTerm

Contents

- Using GraphTerm
  - Introduction
  - Visual cues
  - Navigating folders/opening files
  - Icon display
  - Themes
  - Copy/paste
  - Drag and drop
  - Command recall
  - Inline plots using matplotlib
  - Notebook mode
  - iPad/Android tablet usage
  - Choosing the terminal type
  - Multiple hosts
  - Sessions and “screensharing”
  - Wildcard sessions and multiplexing
  - Webcasting
  - Slideshows
  - Command-line version of pythontutor.com
  - Widgets, sockets, and interactivity
  - Security
  - SSH and port forwarding

## Introduction

(See the README file for information on installing GraphTerm.)

To start the `GraphTerm` server, use the command:

    gtermserver --auth_code=none

Type `gtermserver -h` to view all options. You can use the `--daemon=start` option to run it in the background. The `--host=hostname` option is useful for listening on a public IP address instead of the default `localhost`. The `--lc_export` option can be used to export the GraphTerm environment across SSH via the locale variables (which sometimes works)

Once the server is running, you can open a terminal window on the localhost in the following ways:

> - Specify the `--terminal` option when starting `gtermserver`
> - Within a GraphTerm window, you can select the terminal/new menu option, or type the command `gmenu new` to create a new GraphTerm session

To open a remote terminal window, open up a browser of your choice that supports websockets, such as Google Chrome, Firefox, or Safari (Chrome works best), and enter the following URL:

    http://localhost:8900

Once within the `graphterm` browser page, select the host you wish to connect to and create a new terminal session on the host.

Once you have a terminal, try out the following commands:

    gls <directory>
    gvi <text-filename>

These are graphterm-aware scripts that imitate basic features of the standard `ls` and `vi` commands. To display images as thumbnails, use the `gls -i ...` command. Use the `-h` option to display help information for these commands, and read the UsingGraphicalFeatures tutorial for usage examples.

You can use the command `which gls` to determine the directory containing graphterm-aware commands, to browse for other commands, which include:

> `d3cloud [file]` To display file (or stdin) content as a word cloud

> `gframe [-f] [filename|URL]` To view files/URLs (or HTML from stdin) in inline iframe

> `gimage [-f] [filenames]` To view images inline, or as a fullpage slideshow (with `-f` option)

> `gjs java script command` Execute Javascript in the client browser

> `glandslide [options] file.md` A GraphTerm-aware version of Landslide, a web-based slideshow program

> `gmatplot.py` An inline `matplotlib` plotting demo

> `gmenu item subitem` To access the menubar from the command line

> `gqrcode UR:|text` Display inline QR code

> `greveal [options] file.md` A GraphTerm-aware interface to `reveal.js`, a web-based slideshow program

> `gsnowflake.py` An inline plotting demo for the SVG module `svgwrite`

> `gtweet [-s keywords]|tweet` To send, search, or receive tweets

> `gtutor [...] example.py` A command-line version of the Online Python Tutorial at pythontutor.com

> `gupload [filename|directory]` To upload files from desktop into the terminal

> `yweather [location]` To view weather forecasts

(There is also a sample `gcowsay` command which can be downloaded separately from its Github repository)

## Visual cues

In the default theme, blue color denotes text that can be clicked or tapped. The action triggered by clicking depends upon two factors, whether there is text in the current command line, and whether the Control modifier in the Bottom menu is active. Click on the last displayed prompt to toggle display of the Bottom menu. Clicking on other prompts toggles display of the command output (unless the Control modifier is used, in which case the entire command line is copied and pasted.)

## Navigating folders/opening files

You can navigate folders in GraphTerm just like you would do in a GUI, while retaining the ability to drop back to the CLI at any time. If the current command line is empty, clicking on a folder or filename displayed by the `gls` command will change the current directory to the folder, or cause the file to be opened. If you have typed anything at all in the current command line, even if it is just a space, the clicking action will cause text to be pasted into the command line, without any command being executed. You can edit the pasted text, then press the Enter key to execute it.

## Icon display

Select `icons` in the top menu to activate icon display for commands like `gls`.

## Themes

Themes, selected using the top menu, are a work in progress, especially the 3-D perspective theme (which only works on Chrome/Safari).

## Copy/paste

For certain browsers (e.g., desktop Chrome/Firefox), the usual Command-V or Control-V key sequence should directly paste text from the clipboard. If that doesn’t work, there are a couple of other ways to paste text. First, you can use the keyboard shortcut Control-O to open a popup window, paste the text into the popup window using the browser’s paste menu command or a keyboard shortcut, such as Command/Control-V, and then type Control-O again to insert the text at the GraphTerm cursor location. (The popup paste window can also be accessed using the terminal/paste special menu item.) Alternatively, for some browsers, and on the iPad, you can click on the cursor before beginning the paste operation and then paste the text directly. This second technique may not always work well for text copied from non-plain text sources, such as a web page.

## Drag and drop

Sort of works! You can drag a filename (grabbing the icon does not work) and drop it on a folder, an executable, or the command line. For drag-and-drop between two GraphTerm windows running on the same host, the file will be moved to the destination folder. For windows on two different hosts, the file will be copied. (Graphical feedback for this operation is not properly implemented at this time. Look at the command line for the feedback.)

## Command recall

If the command line is empty, up/down arrows will use the underlying shell for command recall (like Control-P and Control-N). If the command line contains any text, including whitespace, up/down arrows will cause GraphTerm to search for matching previous commands that begin with the text already typed (ignoring any leading whitespace). You can use the right arrow to complete the recalled command (for editing) or use the Enter key to execute it. Typing any other key, including the left arrow, will cancel the command recall process.

## Inline plots using matplotlib

The `gpylab` module in the `bin` directory can be used to start up the python interpreter in the `pylab` mode for inline graphics within a notebook:

    python -i $GTERM_DIR/bin/gpylab.py
    >>> plot([1,2,4])

## Notebook mode

To enter the notebook mode, select notebook/new on the top menu, or type Shift-Enter (or Control-Enter, if you wish to read a notebook file and customize the prompts). You can exit the notebook mode using the top menu bar, or by typing Control-C. Within the notebook mode, use Shift-Enter to execute a cell and move to the next, or Control-Enter for in-place execution. Additional keyboard shortcuts are listed in the help menu.

## iPad/Android tablet usage

Tap on the cursor to display virtual keyboard on the tablet. The Bottom menu, exposed by clicking on the last displayed prompt, can be quite useful on a tablet. (On Android, you may need to tap a couple of more times on the cursor after the keyboard is displayed.)

## Choosing the terminal type

The default terminal type is set to `xterm`, but it may not always work properly. You can also try out the terminal types `screen` or `linux`, which may work better for some purposes. You can use the `--term_type` option when running the server to set the default terminal type, or use the `export TERM=screen` command. (Fully supporting these terminal types is a work in progress.)

## Multiple hosts

More than one host can connect to the GraphTerm server. The local host is connected by default (but this can be disabled using the `--nolocal` option). To connect an additional host, run the following command on the computer you wish to connect:

    gtermhost --server_addr=<serveraddr> <hostname>

where `serveraddr` is the address or name of the computer where the GraphTerm server is running (which defaults to localhost). You can use the `--daemon=start` option to run the `gtermhost` command in the background. By default, the Graphterm server listens for host connections on port 8899. The multiple host feature should only be used within a secure network, not on the public internet.

NOTE: Unlike the `sshd` server, the `gtermhost` command is designed to be run by a normal user, not a privileged user. So different users can connect to the GraphTerm server pretending to be different “hosts” on the same computer. (If you are running a Python server, it can connect directly to the GraphTerm server as a “host”, allowing it to be dynamically introspected and debugged using otrace.)

## Sessions and “screensharing”

For each host, sessions are assigned default names like `tty1` etc. You can also create unique session names simply by using it in an URL, e.g.:

    http://localhost:8900/local/mysession/?qauth=code

The `qauth` code is the same for all terminals on the same browser, and provides a layer of security. Anyone with access to the GraphTerm server can use the session URL to connect to it. This is like “screensharing”, but more efficient, because only the content is shared, not the graphical themes. The first user to create a session “owns” it, until they detach from it. Others connecting to the same session have read-only access, unless they “steal” the session (see the top menu). For example, if you forgot to detach your session at work, you can `ssh` to your desktop from home, use SSH port forwarding (see below) to securely access your work desktop, and then steal the session using your home browser.

NOTE: Although GraphTerm supports multiple users, it currently assumes a mostly cooperative environment, where everyone trusts everyone else. (This may change in the future.)

## Wildcard sessions and multiplexing

A session path is of the form `session_host/session_name`. You can use the shell wildcard patterns `*, ?, []` in the session path. For example, you can open a wildcard session for multiple hosts using the URL:

    http://localhost:8900/*/tty1/?qauth=code

For normal shell terminals, a wildcard session will open a “blank” window, but any input you type in it will be broadcast to all sessions matching the pattern. (To receive visual feedback, you will need to view one or more of the matching sessions at the same time.)

For `otrace` debugging sessions of the form `*/osh`, GraphTerm will multiplex the input and output in wildcard terminals. Your input will be echoed and broadcast, and output from each of the matching sessions will be displayed, preceded by an identifying header (with the special string `ditto` used to indicate repeated output). See the otrace integration section for more information.

NOTE: Multiplexed input/output display cannot be easily implemented for regular shell terminals.

## Webcasting

If you enable the Webcast in the top menu, anyone can use the session URL to view the session, without the need for authentication, but will not be able to steal it. Use this feature with caution to avoid exposing exposing sensitive data.

## Slideshows

The `glandslide` command, which is a slightly modified version of the web-based slide slideshow program Landslide, can be used to create a slideshow from Markdown (.md) or reStructured Text (.rst) files. A few sample `.md` files are provided in the `graphterm/bin/landslide` directory of the distribution. To view a slideshow about GraphTerm, type:

    glandslide -o graphterm-talk1.md | gframe -f

Type `h` for help and `q` to quit the slideshow. (The unmodified Landslide program can also be used, with the `-i` option, but remote sharing will not work.)

The `gimage` command, which displays images inline, can also be used for slideshows and simple presentations. Just `cd` to a directory that has the images for a slideshow, and type:

    gimage -f

To select a subset of images in the directory, you can use a wildcard pattern. For publicly webcasting a slideshow, use the `-b` option.

## Command-line version of pythontutor.com

The command `gtutor` implements a command-line version of the Online Python Tutorial from pythontutor.com. It produces HTML output that can be piped to `gframe` for inline display. To trace the execution of a sample program `example.py`, use it as follows:

    gtutor example.py | gframe -f

More sample programs may be found in the directory `$GTERM_DIR/bin/pytutor/example-code`. Of course, you can use `gtutor` to trace any other (small) python program as well. Type `gtutor -h` to display the command line options. Note: By default, `gtutor` accesses the browser CSS/JS files from pythontutor.com. To use `gtutor` in an offline-mode, you will need to specify the `--offline` option and also download the Online Python Tutorial code from GitHub and copy/rename the main source directory (currently `v3`) as `$GTERM_DIR/www/pytutor` so that GraphTerm can serve the CSS/JS files locally.

Advanced usage: You can embed tutorials within a Landslide/Markdown presentation by including an `iframe` HTML element in the presentation file, with the `src` attribute set to a graphterm URL, such as `http://localhost:8900/local/tutorial`. This will open up a graphterm window where you can either run `gtutor` interactively or use `gframe -f` to display an HTML file created previously using `gtutor`.

## Widgets, sockets, and interactivity

A widget appears as an overlay on the terminal (like picture-in-picture for TVs, or dashboard widgets on the Mac). This is an experimental feature that allows programs running in the background to display information overlaid on the terminal. The widget is accessed by redirecting `stdout` to a Bash `tcp` socket device whose address is stored in the environment variable `GTERM_SOCKET`. For example, the following command will run a background job to open a new terminal in an overlay iframe:

    gframe -f --opacity=0.2 http://localhost:8900/local/new > $GTERM_SOCKET &

You can use the overlay terminal just like a regular terminal, including having recursive overlays within the overlay!

A specific example of widget use is to display live feedback on the screen during a presentation. You can try it out in a directory that contains your presentation slides as images:

    gfeedback 2> $GTERM_SOCKET 0<&2 | gfeed > $GTERM_SOCKET &
    gimage -f

The first command uses `gfeedback` to capture feedback from others viewing the terminal session as a stream of lines from $GTERM_SOCKET. The viewers use the overlaid feedback button to provide feedback. The `stdout` from `gfeedback` is piped to `gfeed` which displays its `stdin` stream as a “live feed” overlay, also via $GTERM_SOCKET. (The `gimage -f` command displays all the images in the directory as a slideshow.)

To display a live twitter feed as an overlay on a presentation, you can use the commands:

    gtweet -w -f -s topic > $GTERM_SOCKET &
    gimage -f

## Security

The GraphTerm is not yet ready to be executed with root privileges. Run it logged in as a regular user. The `--auth_code` option can be used to specify an authentication code required for users connecting to the server. Although multiple hosts can connect to the terminal server, initially, it would be best to use `graphterm` to just connect to `localhost`, on a computer with only trusted users. You can always use SSH port forwarding (see below) to securely connect to the GraphTerm server for remote access. As the code matures, security will be improved through the use of SSL certificates and server/client authentication. (SSL/https support is already built in. Feel free to experiment with it, although it is not yet ready for everyday use.)

## SSH and port forwarding

If you login to a remote computer using SSH, you can use the Action -> Export Environment menu option to set the Bash shell environment variables on the remote computer. This will allow some, but not all, of GraphTerm’s features to work on the remote session. If you wish to use more features, set the `PATH` environment variable on the remote machine to allow access to `gls` and other commands, and also use reverse port forwarding to forward your local port(s) to the remote computer, e.g.:

    ssh -R 8898:localhost:8898 user@remote-computer

Currently, the most secure way to access the GraphTerm server running on a remote computer is to use SSH port forwarding. For example, if you are connecting to your work computer from home, and wish to connect to the GraphTerm server running as `localhost` on your work computer, use the command:

    ssh -L 8900:localhost:8900 user@work-computer

This will allow you to connect to `http://localhost:8900` on the browser on your home computer to access GraphTerm running on your work computer.

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