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

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.

Some implementation like GNU mkdir include mkdir --parents as a more readable alias, but this is not specified in POSIX/Single Unix Specification and not available on many common platforms like macOS, various BSDs, and various commercial Unixes, so it should be avoided.

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

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.

Use the -p flag.

man mkdir
mkdir -p foo

The old tried and true

mkdir /tmp/qq >/dev/null 2>&1

will do what you want with none of the race conditions many of the other solutions have.

Sometimes the simplest (and ugliest) solutions are the best.

You can either use an if statement to check if the directory exists or not. If it does not exits, then create the directory.

1. dir=/home/dir_name

   if [ ! -d $dir ]
   then
        mkdir $dir
   else
        echo "Directory exists"
   fi
   

2. You can directory use mkdir with -p option to create a directory. It will check if the directory is not available it will.

   mkdir -p $dir
   

   mkdir -p also allows to create the tree structure of the directory. If you want to create the parent and child directories using same command, can opt mkdir -p

   mkdir -p /home/parent_dir /home/parent_dir/child1 /home/parent_dir/child2
   

Simple, silent and deadly:

mkdir -p /my/new/dir >/dev/null 2>&1

Or if you want to check for existence first:

if [[ ! -e /path/to/newdir ]]; then
            mkdir /path/to/newdir
fi

-e is the exist test for KornShell.

You can also try googling a KornShell manual.

Referring to man page man mkdir for option -p

   -p, --parents
          no error if existing, make parent directories as needed

which will create all directories in a given path, if exists throws no error otherwise it creates all directories from left to right in the given path. Try the below command. the directories newdir and anotherdir doesn't exists before issuing this command

Correct Usage

mkdir -p /tmp/newdir/anotherdir

After executing the command you can see newdir and anotherdir created under /tmp. You can issue this command as many times you want, the command always have exit(0). Due to this reason most people use this command in shell scripts before using those actual paths.

mkdir -p sam

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

if [ !-d $dirName ];then
     if ! mkdir $dirName; then  # Shorter version. Shell will complain if you put braces here though
     echo "Can't make dir: $dirName"
     fi
fi

Improvement on the 'classic' solution (by Brian Campbell) - to handle the case of symlink to a directory.

[ -d foo/. ] || mkdir foo