How to Code in a Terminal Window

When you want to develop programs, e.g. in Python, on a server, the easiest connection option usually is via ssh access and the ​command line mode in a ​terminal window.

In case, you are not used to working in a terminal, we have gathered a small set of recommendations and tutorial links. The examples will be using the NLP lab server ​aurora as an example.

• for the primary access, see the information for various OSes directly at ​https://aurora.fi.muni.cz
• for basic navigation once you are logged in, see the ​Ubuntu tutorial for working in terminal.
• for easy repeated access, you should setup a SSH key authorization, see the simple ​aurora SSH keys tutorial.
• choose and learn (at least) one in-terminal text editor. An easy option is the ​nano editor - just run nano source.py and start editing, save with Ctrl+S, exit with Ctrl+X. An advanced option is the ​vim editor - we suggest e.g. the ​MIT course VIM intro for an initial engagement with vim. When you start vim source.py, you should press i to edit the text and Esc, :w<Enter> to save changes or :q!<Enter> to discard changes.
• when developing a program, e.g. in Python, we suggest to work in multiple terminal windows. For each window start a separate terminal connection to the server (SSH key authorization comes very handy here), change to the same directory on the server and use for example:
  • one window for source code editing. Do not exit the editor, just save changes and test in another window.
  • one window for running the code and inspecting the results.
  • one window for running a debug (e.g. via python -mpbd source.py).
  • one window for working with auxiliary files, e.g. edit testing data.
• for easy data+code sharing consider using an independent Git repository, e.g. ​https://gitlab.fi.muni.cz/. In that case, you shall store all your source codes and data files in ​Gitlab and just git clone the repository to the server. Use git add, `git commit -a and git push` to promote changes that you make on the server back to ​Gitlab. Use git pull to update the previously cloned repository in the server directory with changes made elsewhere. See e.g. the ​MIT Git info for other details about working with Git.
• how to discover and fix errors - we suggest two standard options: logging and pdb debugging:
  • logging is based on standard Python ​logging library. It allows to supplement your program with messages of various levels of verbosity which can be turned on and off. A simple program may look like {{{#!python import logging

logging.basicConfig( level=logging.DEBUG, format="%(message)s")

logging.info("Program starting") a = 2 b = 2 logging.debug(f"About to sum {a} and {b}") logging.info(f"The result is {a+b}") }}}

• pdb debugging is run from the command line with include specific pdb module. Start the debugging via python -mpdb source.py, then use line-based commands as described in the ​MIT code page. Command q quits the debugger.

• if you are curious enough to get to a terminal pro level, we suggest to go through the full MIT course ​The Missing Semester of Your CS Education.