#!/usr/bin/env bash -x
#!/usr/bin/env bash set -x
Most operating systems, including POSIX, Linux and FreeBSD, allow only a single parameter in the shebang. The example is equivalent to calling
env 'bash -x' instead of
env 'bash' '-x', and it will therefore fail.
The shebang should be rewritten to use at most one parameter. Shell options can instead be set in the body of the script.
macOS X currently allows multiple words in the shebang. Scripts running on OSX exclusively can ignore this warning.
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.