(or "In dash, ... is not supported." when using
#!/bin/sh ssh host cmd &> log
Use the long form instead of the shorthand:
#!/bin/sh ssh host cmd > log 2>&1
&> is a bash and ksh extension for redirecting both stdout and stderr. In dash and POSIX sh, use
If you only intend to target shells that supports this feature, you can change the shebang to a shell that guarantees support, or ignore this warning.
You can use
# shellcheck disable=SC3000-SC4000 to ignore all such compatibility warnings.
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.