> ## Documentation Index > Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt > Use this file to discover all available pages before exploring further. # Bash Directory Check The `-d` operator is a unary file test operator in Bash used to determine whether a specified file path exists and is a directory. It performs a `stat` system call on the provided path, evaluating the file mode metadata to return a standard POSIX exit status. ## Syntax The operator requires a single string argument representing the path. It can be used with the standard `test` builtin, the POSIX test command `[ ]`, or the Bash extended test keyword `[[ ]]`. ```bash theme={"dark"} test -d "$path" [ -d "$path" ] [[ -d "$path" ]] ``` ## Evaluation and Exit Status The operator yields the following exit codes: * **`0` (True):** The path exists in the filesystem **and** its file type is a directory. * **`1` (False):** The path does not exist, **or** the path exists but is a different file type (e.g., regular file, character device, block device, socket, or FIFO). ## Symbolic Link Resolution The `-d` operator dereferences (follows) symbolic links. If the evaluated path is a symlink, the operator checks the file type of the link's ultimate target. * If the symlink resolves to a directory, `-d` returns `0`. * If the symlink resolves to a non-directory, or if it is a broken (dangling) symlink, `-d` returns `1`. ## Technical Nuances * **Quoting and Word Splitting:** When using the POSIX `[ ]` construct, the path variable must be double-quoted (`"$path"`). Failing to quote introduces critical evaluation pitfalls: * **Empty Variables:** If `$path` is empty and unquoted, `[ -d $path ]` expands to `[ -d ]`. Under POSIX `test` rules for a single argument, this evaluates whether the literal string `"-d"` is non-null. Since `"-d"` is not empty, the command silently evaluates to `0` (True). This is a major pitfall, as an empty path check will falsely report that a directory exists. * **Variables with Spaces:** If `$path` contains spaces, Bash performs word splitting. A variable with exactly one space (e.g., `path="a b"`) expands to `[ -d a b ]`, resulting in the error `bash: [: a: binary operator expected`. A variable with two or more spaces (e.g., `path="a b c"`) expands to `[ -d a b c ]`, resulting in `bash: [: too many arguments`. * **Extended Test Construct:** The Bash-specific `[[ ]]` construct suppresses word splitting and pathname expansion. `[[ -d $path ]]` safely handles unquoted empty strings (evaluating to `1`) and spaces without syntax errors, though quoting remains a strict best practice. * **Permissions:** The operator strictly evaluates the file type. It does not verify whether the executing user has read (`-r`), write (`-w`), or execute (`-x`) permissions on the directory itself. However, standard filesystem traversal rules apply; the user must have execute permissions on all parent directories in the path to successfully perform the underlying `stat` operation. * **Explicit Empty Strings:** Passing an explicitly quoted empty string (e.g., `[ -d "" ]` or `[[ -d "" ]]`) always evaluates to `1` (False).

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