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What happens when you run nullglob in empty directory?
In most shells nullglob isn’t the default. That means, for example, if you run this command in an empty directory, it will expand the * glob to a literal *, instead to an empty list of arguments. There are ways to change that behaviour, so that * in an empty directory will return an empty list of arguments, which would seem more intuitive.
Which is an example of nullglob in Bash?
The nullglob option (which BTW is a zsh invention, only added years later to bash ( 2.0 )) would not be ideal in a number of cases. And ls is a good example: (to list the contents of the non-hidden directories whose name ends in .txt, or the non-directory files with the same name patterns)
How to run LS with no argument with nullglob?
With nullglob on would run ls with no argument which is treated as ls — . (list the current directory) if no files match, which is probably worse than calling ls with a literal *.txt as argument¹. Would look for foo on stdin if there’s no txt file.
What is the purpose of null after a type?
The ability to assign null to numeric and Boolean types is especially useful when you are dealing with databases and other data types that contain elements that may not be assigned a value. For example, a Boolean field in a database can store the values true or false, or it may be undefined.
Why does Bash tab completion do not work?
I thought I would also add the following additional explanation for a failure of bash completion- it is too long for a comment and may be useful for someone who has a problem with bash completion, as presumably this is the ‘general’ canonical question to which all duplicates are referred.
How to get nullglob to work in zsh?
You can get that behaviour with zsh with setopt cshnullglob though a more sensible way to do it in zsh would be to use a glob like: In zsh and ksh93, you can also apply nullglob on a per-glob basis, which is a lot saner approach than modifying a global setting: