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BLISS shell



On an ESRF beamline computer, the ESRF BLISS environment has to be activated prior to start BLISS shell:

  • . blissenv to enter conda bliss stable
  • . blissenv -d to enter conda bliss unstable version for developers

From a terminal, after launching a BLISS environment, type:

  • bliss -h or bliss --help to display all command line options

  • bliss -S to display sessions

  • bliss -s sessionname to launch a specific session
(bliss) user@beamline:~/$ bliss --help
Usage: bliss [-l | --log-level=<log_level>] [-s <name> | --session=<name>] [--no-tmux] [--debug]
       bliss [-v | --version]
       bliss [-c <name> | --create=<name>]
       bliss [-h | --help]
       bliss [-S | --show-sessions]
       bliss --show-sessions-only

    -l, --log-level=<log_level>   Log level [default: WARN] (CRITICAL ERROR INFO DEBUG NOTSET)
    -s, --session=<session_name>  Start with the specified session
    -v, --version                 Show version and exit
    -c, --create=<session_name>   Create a new session with the given name
    -h, --help                    Show help screen and exit
    --no-tmux                     Deactivate Tmux usage
    --debug                       Allow debugging with full exceptions and keeping tmux alive after Bliss shell exits
    -S, --show-sessions           Display available sessions and tree of sub-sessions
    --show-sessions-only          Display available sessions names only

What is a session?

To make it easy using a session we have some object automatically created and imported and some startup code that is executed. This can be customized.

Bliss Shell Usage

  • it is a python shell, with all capabilities.
BLISS [2]: 3+2
  Out [2]: 5

BLISS [3]: a=3+2
BLISS [4]: def double(num):
      ...:     return num * 2
BLISS [5]: double(3)
  Out [5]: 6
BLISS [6]: b=_5
BLISS [7]: b
  Out [7]: 6

First steps on Bliss Shell

  • use arrows to select previous commands
  • use _n underscore line number to access the output of the shell
  • Ctrl-c to clear the content of a line
  • Ctrl-r and start typing to perform a search on previous commands
  • Ctrl-o to execute multiline commands (or simply go to the end and press enter)
  • History with F3 (move with arrows, select with space, confirm with Enter)
  • Get informations about an object or function:
    • writing the name of the object, (E.G. type SCAN_SAVING)
    • for functions use help, (E.G. help(ct))
  • more info on command line usage

Command Completion

  • proposes the end of the command while you are typing, Ctrl+space when it does not show
  • gives informations on functions while typing (E.G. ascan(roby, 0, 10, 1, .1, diode))

Typing Helper

  • helps the transition from spec syntax to python adding parentesis and commas
  • I don’t want the help? F7 to disable it

How to exit Bliss Shell?

  • Ctrl-d or exit()
  • Ctrl-b + d to detach from a session (will be still running)


  • It is a Terminal Multiplexer that allows multiple terminals in the same Window
  • Allows multiple people to connect to the same Bliss session
  • Access scan data page with F5

Copy and Paste

  • Copy mode: Scroll the mouse, select in yellow, exit with Enter, q, right-click or scroll down with mouse to the beginning.
  • Multiline Copy: Start from the bottom and go up with the mouse wheel, or use Page-Up
  • Copy a single word with double click
  • Copy a line with triple click
  • Properly format multiline code pressing Shift while pasting or using paste mode (F6)