hchiam / learning-bash-scripts

Learning Bash Scripts

Learning Bash Scripts

Just one of the things I'm learning. https://github.com/hchiam/learning

A nice article on key things to know: https://www.joshwcomeau.com/javascript/terminal-for-js-devs (my own summary notes are below)

To enable running a script upon click, you need to edit permissions. For example, for chrome-incognito-shortcut.app:

chmod 744 chrome-incognito-shortcut.app

Related Repos

https://github.com/hchiam/learning-powershell

https://github.com/hchiam/learning-dependency-cruiser

https://github.com/hchiam/learning-https-server

> and < and >> and << in bash

https://superuser.com/questions/480599/with-regards-to-piping-commands-what-are-the-greater-than-and-less-than

• > = redirect output = "(over)write to", e.g.: echo 'hello' > file.txt
• < = redirect input = "read", e.g.: cat < file.txt (same as just cat file.txt)
• >> = append to end of file, e.g.: echo 'new last line of text' >> file.txt
• cat << EOF >> file.txt = "start multiline input session that ends when you type EOF and hit Enter" (but personally, nano seems to do this simpler)

Useful git commands

• git commit --amend

• git reset HEAD~1 to "un-commit"

• git pull origin dev (if you want to merge commits into dev branch into your local branch) and then type :qa and hit enter. Now you can git push.

• git tag <name-of-tag>; git push --tags (and then you can draft a new release on the same tag name to add details to it on GitHub)

From https://stackoverflow.com/questions/4348590/how-can-i-make-git-ignore-future-revisions-to-a-file/39776107#39776107 :

• git update-index --skip-worktree your-file-to-ignore-future-revisions-for.txt
• git update-index --no-skip-worktree your-file-to-start-watching-revisions-for.txt

From https://www.smashingmagazine.com/make-life-easier-when-using-git/ :

• git status -sb
• git hooks
• Try using git bisect with "binary search" automation to find the breaking change

git bisect start
git bisect good c5ba734 # if c5ba734 is a commit without the bug
git bisect bad 6c093f4 #if 6c093f4 is a commit with the bug
# run test: git bisect run ./test-bug  (or: git bisect run jest)
git bisect bad # if the current commit has the bug
git bisect good # if current commit does not have the bug
# (repeats until find the first commit with the bug)
git bisect reset # or: git bisect reset HEAD (or: git bisect reset <commit-id>)

git rebase -i --exec "yarn test" d294ae9 # test all commits from d294ae9 to HEAD, until hit first failing commit

From https://dev.to/g_abud/advanced-git-reference-1o9j#git-commands :

• git rm --cached <file-name> to stop tracking <file-name> in version control

• git diff --staged

• git diff branch1..branch2

• git commit --amend to add more changes to the last commit

• git cherry-pick <commit-sha> to bring in a commit from a different branch

• git checkout <branch-name> <file-name> to bring in a file from a differnt branch

• git reset <commit-sha>

• git reset --hard HEAD~1 = undo last commit and rewrite history (then git push -f to push rewritten history)

• git reset --hard HEAD~n # where n is the last n commits = undo last n commit and rewrite history (then git push -f to push rewritten history)

• git reset --hard <commit-sha> = undo comments and rewrite history (then git push -f to push rewritten history)

• --soft = uncommit but still staged; --mixed = uncommit+unstage, but changes kept locally; --hard = uncommit+unstage+delete changes

• git stash to save your changes to top of stash stack (add -u to stash untracked files as well)

• git stash list to see what's in your stash

• git stash save "message to go along with changes"

• git stash pop

From https://www.youtube.com/watch?v=ecK3EnyGD8o :

• git stash save nameforlater

  • and then later git stash list (note the index)
  • and then git stash apply <index> to use <index>

• git branch -M main to rename branch to main, and then git push -u origin main (more info)

• git log --graph --oneline --decorate for a pared-down git log

• lots more git tips at a Fireship.io YouTube video

How to revert changes of a git push:

This shows the commit hash: (looks like l0ngStr1ng0fL3t7er5AndNum83rz)

git log

then use the hash of the commit you want to revert: (and when you're in the in-CLI editor, type :qa and then hit Enter)

git revert l0ngStr1ng0fL3t7er5AndNum83rz

How to create a branch with no history

https://stackoverflow.com/a/34954852

git checkout --orphan <name_you_choose_for_orphan_branch>
git commit
git push <remote-name> <branch-name>

Random Notes

Get file info like edit date: stat filename

Example of script used by Travis CI npm run build to copy files to /public folder: copy-to-public-folder.sh

Example of script used to generate and insert a package SemVer number for a JS file: package.sh

Exit/quit:

exit

Get list of globally installed packages

yarn global list

npm list -g --depth 0 for just top-level

npm list -g browser-sync or a specific package (this example checks if browser-sync is installed globally)

npm scripts that accept parameters

Examples I set up in package.json:

{
  "test": "tsc $npm_config_name.ts --lib es6,dom && node $npm_config_name.js",
  "demo": "echo \"HELLO $npm_config_file_name.ts GOODBYE (\\$npm_config_whatever will match --whatever=...)\""
}

So you can do this:

npm run demo --file_name=someFileName
# prints out: HELLO someFileName.ts GOODBYE [...]

and:

npm run test --name=sameFileName
# will run: tsc sameFileName.ts --lib es6,dom && node sameFileName.js

Install package without dynamic version (i.e. without caret ^)

npm install <package-name> --save-exact

so you get 1.2.3 instead of ^1.2.3 in your package.json

https://stackoverflow.com/questions/58638817/what-is-the-purpose-of-using-save-exact#:~:text=--save-exact%20will%20generate%20the%20next%20package.json%20code

Actually upgrade node

You can upgrade to the latest npm with npm install -g npm@latest

But installing node manually doesn't always work, and using n or clean cache didn't seem to work for me. https://stackoverflow.com/questions/23940172/not-seeing-latest-version-when-updating-node-js-via-installer-msi-windows-7/31229369#31229369

For Mac/OSX, try this first:

brew install node

Otherwise this:

nvm install node --lts
node -v

If you accidentally installed the latest but want to downgrade to the last stable instead:

nvm install 14.15.0 # whatever the latest unstable versioni on https://nodejs.org/en/
nvm use 14.15.0

switching from bash to zsh: (and back)

https://github.com/hchiam/learning-zsh

Format whole directory instead of waiting for each file save in VSCode

prettier --write .

or

npx prettier --write .

how to sync forked repo with the original repo

https://stackoverflow.com/questions/7244321/how-do-i-update-or-sync-a-forked-repository-on-github

git remote add upstream https://github.com/<owner>/<repo>.git
git fetch upstream

gh CLI commands

https://github.com/hchiam/learning-gh

setting up GitHub PATs (Personal Access Tokens)

For gh CLI: copy your PAT, run gh auth login, and paste your PAT when prompted to.

For npm pkg: copy your PAT, open ~/.npmrc, and paste your PAT to be the "TOKEN" part of a string //npm.pkg.github.com/:_authToken=TOKEN in that ~/.npmrc file.

quickly set up a basic server to serve index.html (or whatever's in the current folder)

python3 -m http.server 8000

or set up shortcut srv in .bash_profile:

alias srv='python3 -m http.server 8000'

https://www.joshwcomeau.com/javascript/terminal-for-js-devs

• Bash ≈ Zsh
• the terminal is kinda like the console log in browser dev tools, but can switch between shell languages
• echo ≈ console.log
• $ notation is just for start of prompt
• pwd = print the current working directory folder path
• ls = list current folder files/subfolders
  • ls -la = -long data too like updated dates, and -all files including hidden files/folders
• cd = change directory
• ~ = home folder, like /Users/yourusernamehere
• . = current folder
• .. = parent folder
• use the tab key to auto-complete!
• rm = remove
  • rm -r foldername = remove foldername and -recursively inside it too
  • rm -rf foldername = do that, but -force remove regardless of permissions
• man somecommand = show a printout of the manual for somecommand
  • hit q to quit (arrow keys to scroll)
• ping 8.8.8.8 = continuously check latency against IP address 8.8.8.8 (Google's DNS server), which can be used to continuously check if the server is online (Ctrl+c or Ctrl+d to stop)
• - = "previous"
  • cd - = toggle to previous folder
  • git checkout - = toggle to previously-checked-out branch
• alias hi='echo "Hello world!"'
  • now you can just do hi to get a printout of Hello world!
• command1 && command2 = do command1 and then to command2
• stuck in Vi/Vim? Ctrl+c won't work! hit Escape -> : -> q! -> Enter
• common web dev tasks: https://www.joshwcomeau.com/javascript/terminal-for-js-devs/#common-development-tasks
  • reinstall dependencies: rm -rf node_modules; npm install;