Python general

• Error catching
  Python

  assert <expression> , "<message>"
  # OR
  if not <expression>:
    raise AssertionError("<message>")
    # some exception types that can be used:
    # AssertionError, IndexError, RunTimeError, TypeError, ValueError, ZeroDivisionErrore
  # OR use try except
  try:
  print("Hello")
  except:
  print("Something went wrong") # if error in try
  else:
  print("Nothing went wrong")  # if no error in try
  # try except with finally
  try:
  print(x)
  except:
  print("Something went wrong")
  finally:
  print("The 'try except' is finished")  # finally block is executed regardless of errors or no errors in try
  

Linux and Git Commands

• Sometimes you may want to keep a watch on something:

  watch -n <number_of_seconds> <command>
  

• Reduce brightness below minimum (replace 2070)

  cat /sys/class/backlight/intel_backlight/brightness
  sudo su -c "echo 2070 >/sys/class/backlight/intel_backlight/brightness"
  

• Mute an application :

  pacmd list-sink-inputs
  pacmd set-sink-input-mute <index> true(/false)
  

• Setting upstream: sometimes you may want a local branch to track another remote branch

  # check which branch tracks what
  git branch -vv
  # set upstream
  git branch -u <remote>/<branch>
  # or If you just wish to push once to another remote branch 
  git push <remote> <local_branch>:<remote_name>
  

• sshfs: One of the most handy commands when working on remote server

  sshfs USER@IP:/$PATH $LOCAL_PATH
  

• scp: copy recursively all files and folders

  scp -rp sourcedirectory user@dest:/path
  # -r for recursive and -p to preserve modification times and modes
  

• Screen: another handy function when working remotely, to prevent creating multiple sessions locally

  # make screen
  screen -S myscreen 
  # list all 
  screen -ls
  # attach to a session
  screen -r <name>
  # detach
  screen -d <name>
  # detach
  C-a d
  # kill
  C-a k
  

Miscellaneous

• Auto reload modules in Jupyter

  # add to beginning of notebook
  %load_ext autoreload
  %autoreload 2
  

• Jekyll to build site locally

  sudo apt-get install ruby-full build-essential zlib1g-dev
  gem install jekyll bundler
  bundle install
  bundle exec jekyll serve --watch --trace
  

• Run Jupyter Nodebook on remote server via ssh

  # open it on remote
  sasha@remote $ jupyter notebook --no-browser --port=8887
  # Tunnel through ssh on local
  ssh -N -L localhost:8888:localhost:8887 sasha@remote
  

• Download all google search images with filters: Fatkun batch extension

  https://chrome.google.com/webstore/detail/fatkun-batch-download-ima/nnjjahlikiabnchcpehcpkdeckfgnohf?hl=en
  

• ROS Basics:
  1. https://tarangshah.com/blog/2017-04-01/ros-basics-1-nodes-topics-services-actions/
  2. https://www.youtube.com/watch?v=DBFYZRMLr70&list=PLK0b4e05LnzZWg_7QrIQWyvSPX2WN2ncc

References:

• https://arnavdhamija.com/computer-tips/

… to be continued