1ac454a384 Enable ShellCheck rules (Hennadii Stepanov)
Pull request description:
Enable some simple ShellCheck rules.
Note for reviewers: `bash` and `shellcheck` on macOS are different from ones on Ubuntu.
For local tests the latest `shellcheck` version 0.6.0 should be used (see #15166).
ACKs for top commit:
practicalswift:
utACK 1ac454a384
dongcarl:
utACK 1ac454a
fanquake:
ACK 1ac454a384
Tree-SHA512: 8d0a3a5c09fe1a0c22120178f5e6b80f81f746f8c3356b7701ff301c117acb2edea8fe08f08fb54ed73f94b1617515fb239fa28e7ab4121f74872e6494b6f20e
Downloading all the binaries of all platforms can take quite long,
especially for slow connections, which may deter people from using
this script and, therefore, to disregard security altogether.
This change introduces the new possibility of specifying the
platform along with the version number, so that only the binaries
that contain the platform name are downloaded.