That seems to be zsh-specific syntax that is like ">" except that overrides a CLOBBER setting[1]. However, it won't work in bash. It will create file named "!"

That seems to be zsh-specific syntax that is like ">" except that overrides a CLOBBER setting[1]. However, it won't work in bash. It will create file named "!" with the same contents as "filename". It is equivalent to "cat /dev/null filename > !". (Bash lets you put the redirection almost anywhere, including between one argument and another.) --- [1] See https://zsh.sourceforge.io/Doc/Release/Redirection.html https://zsh.sourceforge.io/Doc/Release/Redirection.html