How to mkdir only if a dir does not already exist?

Question

I am writing a shell script to run under the KornShell (ksh) on AIX. I would like to use the mkdir command to create a directory. But the directory may already exist, in which case I do not want to do anything. So I want to either test to see that the directory does not exist, or suppress the "File exists" error that mkdir throws when it tries to create an existing directory.

Any thoughts on how best to do this?

Answer 1

mkdir -p sam

• mkdir = Make Directory
• -p = --parents
• (no error if existing, make parent directories as needed)

Answer 2

Use the -p flag.

man mkdir
mkdir -p foo

Answer 3

Try mkdir -p:

mkdir -p foo

Note that this will also create any intermediate directories that don't exist; for instance,

mkdir -p foo/bar/baz

will create directories foo, foo/bar, and foo/bar/baz if they don't exist.

If you want an error when parent directories don't exist, and want to create the directory if it doesn't exist, then you can test for the existence of the directory first:

[ -d foo ] || mkdir foo

Answer 4

This should work:

$ mkdir -p dir

or:

if [[ ! -e $dir ]]; then
    mkdir $dir
elif [[ ! -d $dir ]]; then
    echo "$dir already exists but is not a directory" 1>&2
fi

which will create the directory if it doesn't exist, but warn you if the name of the directory you're trying to create is already in use by something other than a directory.

Answer 5

mkdir does not support -p switch anymore on Windows 8+ systems.

You can use this:

IF NOT EXIST dir_name MKDIR dir_name

Answer 6

directory_name = "foo"

if [ -d $directory_name ]
then
    echo "Directory already exists"
else
    mkdir $directory_name
fi