UNIX for Dummies Questions & Answers

Hi,

- The first question I have concerns a very fundamental aspect of a unix OS. Specifically, does unix treat everything as a file (ie a directory is just a type of file)?

- The reason I ask is that I am trying to determine which BASH unary operator I would to use to determine whether or not a directory exists. I am writing a BASH shell script where the user defines a directory in which data files will be placed. I would then like to check that the specified directory exists, and if not the script will error.

I am inclined to use the -d operator (file is a directory). Does this have an implicit test for existence?

The other choice I can think of is the -e operator (file exists). This would assume that unix treats directories as files.

I appreciate any help. Thank you.

Mike

Yes everything is a file. files have "magic" words at the beginning that identifies what the file is.

The -d test is just fine to determine the existence of a directory. After all, some user could have created a regular file by the same name.