Commits & Commit Messages

Here are a few important guidelines w.r.t to git and GitHub:

1. Push your work in a separate branch and create a PR when ready. PRs are always squashed so you can push as many corrections as you want to a PR.

2. Strive for clear and short commit messages. At a minimum, start with an 80-character summary, with verbs in present tense.

3. Add the --signoff or -s flag to git commit. This flag is intended to certify that you have created the patch in question, or that you certify that to the best of your knowledge, it was created under an appropriate open-source license, or that it has been provided to you by someone else under those terms.

To admins: You can always add Signed-off-by: Name <email> when squashing commits.

PaSh on Docker: A Pocket Guide

This is a pocket guide for running PaSh in a docker container.

docker pull binpash/pash
docker run --name pash-play -it pash

git config --global user.name "FIRST_NAME LAST_NAME"
git config --global user.email "YOUR_EMAIL@example.com"
ssh-keygen -t rsa -b 4096 -C "YOUR_EMAIL@example.com"

docker images                    # shows all images in the system
docker ps -a | grep pash         # shows all containers with name pash
docker run --name NN pash/18.04  # creates a writable container (add `-it` for interactive)
docker start -i NN               # starts container (add `-i` to drop straight into shell)
docker attach NN                 # non-interactive -> interactive
<CTL+p>, then <CTL+q>            # interactive -> non-interactive
docker cp A B                    # copy host<->container; A B can be `NN:/x/y/z` or `lo/c/al`

Installing WSL on Windows

To run PaSh on Windows without Docker, a user needs to install WSL (Windows Subsystem for Linux). WSL lets developers run a GNU/Linux environment — including most command-line tools, utilities, and applications — directly on Windows, unmodified, without the need to setup a traditional virtual machine or use dualboot.

Microsoft docs and troubleshooting detail the installation process; below is a short guide. All commands below should be run in an Administrator Poweshell prompt.

wsl --list --online

wsl --install -d <distribution-name-from-above>

Restart-Computer

dism.exe /online /enable-feature /featurename:Microsoft-Windows-Subsystem-Linux /all /norestart

dism.exe /online /enable-feature /featurename:VirtualMachinePlatform /all /norestart

Restart-Computer

(New-Object System.Net.WebClient).DownloadFile("https://wslstorestorage.blob.core.windows.net/wslblob/wsl_update_x64.msi", "C:/Windows/Temp/wsl2.msi");
msiexec /i "C:/Windows/Temp/wsl2.msi";
Remove-Item "C:/Windows/Temp/wsl2.msi"

wsl --set-default-version 2

Restart-Computer

Docker TODO

Using GNU Screen

We often use GNU screen, a terminal multiplexer, for pair programming. GNU screen has two benefits: (1) it allows a session to continue executing even after one detaches and closes the terminal window, which is useful for executing long-running processes such as PaSh’s experiments; and (2) it allows multiple people to share a session, with the ability to read and write in the terminal window as if it was a single person.

Here are commands related to launching a screen session: * screen -> start a new session * screen -ls -> show all screen sessions in this machine * screen -x <ID> -> attach to screen with id <ID>, as shown by -ls above. * screen -x <user>/<pash> -> attach to session pash of user user, assuming it exists/running;

When in a screen session, all screen-related commands are prefixed by ctr-a (which means pressing ctrl and a together, and then pressing the followup character). Here are the 5 most useful commands: * ctrl-a c -> create­a new window in the current session * ctrl-a " -> show all windows and choose using up/down arrows * ctr-a <N> -> go to window , where is 0..9 inclusive * ctrl-a ctrl-a -> fast-toggle between latest windows * ctrl-a d -> detach window, to exit without closing screen

A slightly more extended pocket guide in this gist.

Pushing to new branches

To keep the main branch free of breakage, we often push technical work in new branches. To do this, from the main/master branch on your local machine:

git checkout -b <NAME>    # create a new branch and switch to it
git push -u origin <NAME> # push the new branch as a new branch on github

You can always fetch changes into the main/master:

git checkout master        # switch to main/master
git pull                   # fetch remote changes
git checkout <NAME>        # switch back to your branch
git merge master           # fetch changes from main/master

(You can use rebase instead of merge if your branch is local and hasn’t been pushed to GitHub, but merge if your branch is already pushed.)

Process for Using EC2 Instance

A reason to use Amazon Elastic Compute Cloud (EC2) is having insufficient computing power in your local machine. The steps to do are as follows. The generated key is of the form user@hostname.

1. Make changes in local Docker
2. git push in local Docker
3. Run scripts/ssh-install.sh ~/.ssh/id_rsa <hostname> in cloned pash repository on local machine (pulls changes from GitHub)
4. Run ssh <SSH Key>. The changes will have automatically been transferred over. Can confirm with git log.