message-1:
Apple's Xcode app is essential for app development, test, etc, etc, etc.
Start the "Terminal" app, inside the Applications > Utilities.
To view installed Xcode version number, run this/below command inside the Terminal window :
$ xcodebuild -version
... If output is not-showing version number then Xcode is not-installed.
Many programming related apps still need separate installation of apple's CLT (Command Line Tool),
you may download CLT's DMG installer file from apple Developers website (a free type dev account creation is required there), then you can run the CLT installer pkg/app in DMG file),
or, run the below command in "Terminal" window:
$ xcode-select --install
To view installed CLT version number, run this command:
$ pkgutil –pkg-info=com.apple.pkg.CLTools_Executables
... If above command's output is not-showing verison number or showing msg that “…No receipt…” etc, then CLT is not installed, or its already bundled inside+with Xcode.
To view all pre-installed pkgs you may run :
$ pkgutil –pkgs
Run below command combinations in Terminal window, it will show installed CLT's compiler/builder component's version numbers:
$ gcc -v && llvm-gcc -v && clang -v
You may also run xcrun clang command, & see what it outputs:
UserMacBook:~ username$ xcrun clang
clang: error: no input files
... in above, if output is NOT this message clang: error: no input files, then either CLT installation has error or executable files are not placed in PATH environment variable correctly yet.
Run below command in Terminal window:
$ defaults write com.apple.Finder AppleShowAllFiles true
... Above command only makes the files viewable inside file-browser ("Finder", "Terminal", etc) type of software, it does not actually change any file-attributes.
After above command, user need to: either restart the mac computer, or run below command in Terminal window:
$ sudo /usr/bin/killall Finder /System/Library/CoreServices/Finder.app
In macOS "Finder" or inside any other file browsing window, a user can also press below THREE buttons/keys (in keyboard) altogether ONCE to show/view all HIDDEN files/folders:
[Command⌘] + [Shift⇧] + [.>]
Those who use windows-keyboard:
[WindowsFlag⊞] + [Shift⇧] + [.>]
... These buttons, actually does not remove any real "Hidden" file/folder attribute to make a file/folder visible, these buttons only tells the file-browsing app to make the real "Hidden" file/folder visible, inside the browsing window, temporarily.
When user press-es above three buttons again, file-browsing-window will make the real HIDDEN files/folders, invisible again.
By default in macOS, the "Finder" will keep most of the file extension hidden. But we need to see all file's extension to see FULL filename, so that we can be sure & not make mistake, when we will specify/use file/folder.
To view all file's extension, do below steps:
in macOS > start “Finder” app > goto main menu > Finder > Preferences > Advanced > select the "Show All Filename Extensions" option.
macOS by default uses a very old version of bash shell. Many prefers bash shell over the newer zsh shell, but they want newer bash shell, but apple wont add/include newer version bash shell.
So users usually load latest stable bash shell via 3rd-party package-manager software, such as : MacPorts , HomeBrew , pkgsrc , etc.
I prefer bash shell.
I prefer MacPorts pkkg-mngr, because HomeBrew pkg-mngr shares user's usage data with Google from beginning by-default, despite knowing Google records for-ever. (ByTheWay, MacPorts was developed 7 years before Brew/HomeBrew).
Change the default shell in Terminal on Mac - Apple Support
Use zsh as the default shell on your Mac - Apple Support
Change zsh to other/different shell - Apple Support
When/Once you decide & setup shell (in macOS Terminal) what you want to use,
then follow above links to setup the shell.
Different shell has different config file to control shell activities, pls see this again.
Then you have to setup/fix the "PATH" : 1 , 2 , 3 .
PATH is a "search-sequence" to allow+find a specific file among many many folders, folder-trees.
Command Line Primer (please follow sub-links inside that webpage to learn/know/refresh more).
I usually keep a shell-script file called "DevMode.sh" in my home directory inside macOS.
in Terminal, inside a specific tab, i run that shell-script, to switch into development mode.
By-default, your mac computer should not be running in full development mode, then unwanted activities will have more opportunities to run/do more harmful/abusive activities, because more "power"/tools are available.
inside Terminal, inside a tab, a user can start a development mode, to do development/programing related works, then close that if you want-to or need-to, ... that is more safer.
Anyway, you have to find a balance that suits you, w/o sacrificing key/major security/safety.
... pls see next message ...