start-shared-test-validator.sh should test for and ask users to install 'flock' and 'pidof' (they're not there by default on macOS)

[mikemaccana]

Overview

Following the instructions per solana-web3.js/examples/README.md, all the examples fail to run on a new mac since Flock isn't there by default.

Steps to reproduce

% pwd
/Users/mike/Code/solana-web3.js/examples/transfer-lamports
mike@Mac transfer-lamports % pnpm start

> @solana/example-transfer-lamports@ prestart /Users/mike/Code/solana-web3.js/examples/transfer-lamports
> turbo --output-logs=errors-only compile:js compile:typedefs

turbo 2.2.3

• Packages in scope: @solana/example-transfer-lamports
• Running compile:js, compile:typedefs in 1 packages
• Remote caching disabled

 Tasks:    74 successful, 74 total
Cached:    74 cached, 74 total
  Time:    1.611s >>> FULL TURBO


> @solana/example-transfer-lamports@ start /Users/mike/Code/solana-web3.js/examples/transfer-lamports
> start-server-and-test '../../scripts/start-shared-test-validator.sh' http://127.0.0.1:8899/health run:example

1: starting server using command "../../scripts/start-shared-test-validator.sh"
and when url "[ 'http://127.0.0.1:8899/health' ]" is responding with HTTP status code 200
running tests using command "npm run run:example"

../../scripts/start-shared-test-validator.sh: line 24: flock: command not found
Error: server closed unexpectedly
    at ChildProcess.onClose (/Users/mike/Code/solana-web3.js/node_modules/.pnpm/[email protected]/node_modules/start-server-and-test/src/index.js:83:14)
    at ChildProcess.emit (node:events:518:28)
    at maybeClose (node:internal/child_process:1104:16)
    at ChildProcess._handle.onexit (node:internal/child_process:304:5)
 ELIFECYCLE  Command failed with exit code 1.

Description of bug

I don't have a Linux box to test but I bet flock is probably there by default, on mac you need to add https://formulae.brew.sh/formula/flock

We want to ask people to install Homebrew and then brew install flock

After this the examples work.

Another possible solution would be to remove the flock and pidof requirements if this is possible/safe.

[steveluscher]

Previously, #2042.