shellcheck: check shebang first before linting instead of defaults to POSIX sh

[Andrei Jiroh Halili]

About this Issue

Currently, the extension will assume the shell script is written in purely dash (aka POSIX mode for bash), even through there's an explict usage of shebang pointing to bash.

[Alexander Taran]

Agree, extension ignores following shebang: #!/usr/bin/env bash as well. It will check with sh rules, which is wrong.

I have found 2 workarounds:

• Rename script to *.bash. Which usually is not suitable for me.
• Set this in global or local settings.json. Restart|Reload of vscode is needed in this case:

  "linter.linters": {
    "shellcheck": {
      "args": ["--shell=bash"]
    }
  }

The latter works for me in most times as I am not pinned to core sh shell.

It would be great if extension work correctly with shebangs.

[carlfischerjba]

I see that this extension calls ShellCheck with an explicit --shell sh or --shell bash based on the file extension here. I'm not sure why that's necessary when the command line tool appears to figure out the dialect from the shebang rather than the extension. The extension timonwong.shellcheck appears to use a similar approach but only for extensions .ksh, .bash and .dash.

[astaruch]

When installed both fnando.linter and timonwong.shellcheck, disabling/uninstall the vscode-linter helps to solve problems with Bash scripts as a quick workaround.

[Sorin Sbarnea]

@fnando Adding the explicit --shell=sh argument is a huge bug as it prevents shellcheck from correctly using the shebang of the file.

Sadly I will uninstall this extension as it is causing a huge amount of false-positives.