createDir dir creates a new directory dir which is initially empty, or as near to empty as the operating system allows.

The operation may fail with:

• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES]
• isAlreadyExistsError / AlreadyExists The operand refers to a directory that already exists. [EEXIST]
• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument The operand is not a valid directory name. [ENAMETOOLONG, ELOOP]
• NoSuchThing There is no path to the directory. [ENOENT, ENOTDIR]
• ResourceExhausted Insufficient resources (virtual memory, process file descriptors, physical disk space, etc.) are available to perform the operation. [EDQUOT, ENOSPC, ENOMEM, EMLINK]
• InappropriateType The path refers to an existing non-directory object. [EEXIST]

createDirIfMissing parents dir creates a new directory dir if it doesn't exist. If the first argument is True the function will also create all parent directories if they are missing.

Ensure that a directory exists creating it and its parent directories if necessary. This is just a handy shortcut:

ensureDir = createDirIfMissing True

Since: 0.3.1

removeDir dir removes an existing directory dir. The implementation may specify additional constraints which must be satisfied before a directory can be removed (e.g. the directory has to be empty, or may not be in use by other processes). It is not legal for an implementation to partially remove a directory unless the entire directory is removed. A conformant implementation need not support directory removal in all situations (e.g. removal of the root directory).

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument The operand is not a valid directory name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError / NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
• UnsatisfiedConstraints Implementation-dependent constraints are not satisfied. [EBUSY, ENOTEMPTY, EEXIST]
• UnsupportedOperation The implementation does not support removal in this situation. [EINVAL]
• InappropriateType The operand refers to an existing non-directory object. [ENOTDIR]

removeDirRecur dir removes an existing directory dir together with its contents and sub-directories. Within this directory, symbolic links are removed without affecting their targets.

renameDir old new changes the name of an existing directory from old to new. If the new directory already exists, it is atomically replaced by the old directory. If the new directory is neither the old directory nor an alias of the old directory, it is removed as if by removeDir. A conformant implementation need not support renaming directories in all situations (e.g. renaming to an existing directory, or across different physical devices), but the constraints must be documented.

On Win32 platforms, renameDir fails if the new directory already exists.

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument Either operand is not a valid directory name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError / NoSuchThing The original directory does not exist, or there is no path to the target. [ENOENT, ENOTDIR]
• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
• ResourceExhausted Insufficient resources are available to perform the operation. [EDQUOT, ENOSPC, ENOMEM, EMLINK]
• UnsatisfiedConstraints Implementation-dependent constraints are not satisfied. [EBUSY, ENOTEMPTY, EEXIST]
• UnsupportedOperation The implementation does not support renaming in this situation. [EINVAL, EXDEV]
• InappropriateType Either path refers to an existing non-directory object. [ENOTDIR, EISDIR]

listDir dir returns a list of all entries in dir without the special entries (. and ..). Entries are not sorted.

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument The operand is not a valid directory name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError / NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EACCES]
• ResourceExhausted Insufficient resources are available to perform the operation. [EMFILE, ENFILE]
• InappropriateType The path refers to an existing non-directory object. [ENOTDIR]

The same as listDir but returns relative paths.

Since: 1.4.0

Similar to listDir, but recursively traverses every sub-directory excluding symbolic links, and returns all files and directories found. This can fail with the same exceptions as listDir.

Note: before version 1.3.0, this function followed symlinks.

The same as listDirRecur but returns paths that are relative to the given directory.

Since: 1.4.2

Copies a directory recursively. It does not follow symbolic links and preserves permissions when possible. If the destination directory already exists, new files and sub-directories complement its structure, possibly overwriting old files if they happen to have the same name as the new ones.

Note: before version 1.3.0, this function followed symlinks.

Note: before version 1.6.0, the function created empty directories in the destination directory when the source directory contained directory symlinks. The symlinked directories were not recursively traversed. It also copied symlinked files creating normal regular files in the target directory as the result. This was fixed in the version 1.6.0 so that the function now behaves much like the cp utility, not traversing symlinked directories, but recreating symlinks in the target directory according to their targets in the source directory.

The same as copyDirRecur, but it does not preserve directory permissions. This may be useful, for example, if the directory you want to copy is “read-only”, but you want your copy to be editable.

Note: before version 1.3.0, this function followed symlinks.

Note: before version 1.6.0, the function created empty directories in the destination directory when the source directory contained directory symlinks. The symlinked directories were not recursively traversed. It also copied symlinked files creating normal regular files in the target directory as the result. This was fixed in the version 1.6.0 so that the function now behaves much like the cp utility, not traversing symlinked directories, but recreating symlinks in the target directory according to their targets in the source directory.

Since: 1.1.0

Action returned by the traversal handler function. The action controls how the traversal will proceed.

Note: in version 1.4.0 the type was adjusted to have the b type parameter.

Since: 1.2.0

Traverse a directory tree using depth first pre-order traversal, calling a handler function at each directory node traversed. The absolute paths of the parent directory, sub-directories and the files in the directory are provided as arguments to the handler.

The function is capable of detecting and avoiding traversal loops in the directory tree. Note that the traversal follows symlinks by default, an appropriate traversal handler can be used to avoid that when necessary.

Since: 1.2.0

The same as walkDir but uses relative paths. The handler is given dir, directory relative to the directory where traversal begins. Sub-directories and files are relative to dir.

Since: 1.4.2

Similar to walkDir but accepts a Monoid-returning output writer as well. Values returned by the output writer invocations are accumulated and returned.

Both, the descend handler as well as the output writer can be used for side effects but keep in mind that the output writer runs before the descend handler.

Since: 1.2.0

The same as walkDirAccum but uses relative paths. The handler and writer are given dir, directory relative to the directory where traversal begins. Sub-directories and files are relative to dir.

Since: 1.4.2

Obtain the current working directory as an absolute path.

In a multithreaded program, the current working directory is a global state shared among all threads of the process. Therefore, when performing filesystem operations from multiple threads, it is highly recommended to use absolute rather than relative paths (see: makeAbsolute).

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• isDoesNotExistError or NoSuchThing There is no path referring to the working directory. [EPERM, ENOENT, ESTALE...]
• isPermissionError or PermissionDenied The process has insufficient privileges to perform the operation. [EACCES]
• ResourceExhausted Insufficient resources are available to perform the operation.
• UnsupportedOperation The operating system has no notion of current working directory.

Change the working directory to the given path.

In a multithreaded program, the current working directory is a global state shared among all threads of the process. Therefore, when performing filesystem operations from multiple threads, it is highly recommended to use absolute rather than relative paths (see: makeAbsolute).

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument The operand is not a valid directory name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError or NoSuchThing The directory does not exist. [ENOENT, ENOTDIR]
• isPermissionError or PermissionDenied The process has insufficient privileges to perform the operation. [EACCES]
• UnsupportedOperation The operating system has no notion of current working directory, or the working directory cannot be dynamically changed.
• InappropriateType The path refers to an existing non-directory object. [ENOTDIR]

Run an IO action with the given working directory and restore the original working directory afterwards, even if the given action fails due to an exception.

The operation may fail with the same exceptions as getCurrentDir and setCurrentDir.

Return the current user's home directory.

The directory returned is expected to be writable by the current user, but note that it isn't generally considered good practice to store application-specific data here; use getAppUserDataDir instead.

On Unix, getHomeDir returns the value of the HOME environment variable. On Windows, the system is queried for a suitable path; a typical path might be C:/Users/<user>.

The operation may fail with:

• UnsupportedOperation The operating system has no notion of home directory.
• isDoesNotExistError The home directory for the current user does not exist, or cannot be found.

Obtain the path to a special directory for storing user-specific application data (traditional Unix location).

The argument is usually the name of the application. Since it will be integrated into the path, it must consist of valid path characters.

• On Unix-like systems, the path is ~/.<app>.
• On Windows, the path is %APPDATA%/<app> (e.g. C:/Users/<user>/AppData/Roaming/<app>)

Note: the directory may not actually exist, in which case you would need to create it. It is expected that the parent directory exists and is writable.

The operation may fail with:

• UnsupportedOperation The operating system has no notion of application-specific data directory.
• isDoesNotExistError The home directory for the current user does not exist, or cannot be found.

Return the current user's document directory.

The directory returned is expected to be writable by the current user, but note that it isn't generally considered good practice to store application-specific data here; use getAppUserDataDir instead.

On Unix, getUserDocsDir returns the value of the HOME environment variable. On Windows, the system is queried for a suitable path; a typical path might be C:/Users/<user>/Documents.

The operation may fail with:

• UnsupportedOperation The operating system has no notion of document directory.
• isDoesNotExistError The document directory for the current user does not exist, or cannot be found.

Return the current directory for temporary files.

On Unix, getTempDir returns the value of the TMPDIR environment variable or "/tmp" if the variable isn't defined. On Windows, the function checks for the existence of environment variables in the following order and uses the first path found:

• TMP environment variable.
• TEMP environment variable.
• USERPROFILE environment variable.
• The Windows directory

The operation may fail with:

• UnsupportedOperation The operating system has no notion of temporary directory.

The function doesn't verify whether the path exists.

Obtain the paths to special directories for storing user-specific application data, configuration, and cache files, conforming to the XDG Base Directory Specification. Compared with getAppUserDataDir, this function provides a more fine-grained hierarchy as well as greater flexibility for the user.

It also works on Windows, although in that case XdgData and XdgConfig will map to the same directory.

Note: The directory may not actually exist, in which case you would need to create it with file mode 700 (i.e. only accessible by the owner).

Note also: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

Since: 1.2.1

Similar to getXdgDir but retrieves the entire list of XDG directories.

On Windows, XdgDataDirs and XdgConfigDirs usually map to the same list of directories unless overridden.

Refer to the docs of XdgDirectoryList for more details.

Since: 1.5.0

Class of things (Paths) that can be canonicalized, made absolute, and made relative to a some base directory.

Append stringly-typed path to an absolute path and then canonicalize it.

Since: 0.3.0

The same as resolveFile, but uses current working directory.

Since: 0.3.0

The same as resolveFile, but for directories.

Since: 0.3.0

The same as resolveDir, but uses current working directory.

Since: 0.3.0

removeFile file removes the directory entry for an existing file file, where file is not itself a directory. The implementation may specify additional constraints which must be satisfied before a file can be removed (e.g. the file may not be in use by other processes).

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument The operand is not a valid file name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError / NoSuchThing The file does not exist. [ENOENT, ENOTDIR]
• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
• UnsatisfiedConstraints Implementation-dependent constraints are not satisfied. [EBUSY]
• InappropriateType The operand refers to an existing directory. [EPERM, EINVAL]

renameFile old new changes the name of an existing file system object from old to new. If the new object already exists, it is atomically replaced by the old object. Neither path may refer to an existing directory. A conformant implementation need not support renaming files in all situations (e.g. renaming across different physical devices), but the constraints must be documented.

The operation may fail with:

• HardwareFault A physical I/O error has occurred. [EIO]
• InvalidArgument Either operand is not a valid file name. [ENAMETOOLONG, ELOOP]
• isDoesNotExistError / NoSuchThing The original file does not exist, or there is no path to the target. [ENOENT, ENOTDIR]
• isPermissionError / PermissionDenied The process has insufficient privileges to perform the operation. [EROFS, EACCES, EPERM]
• ResourceExhausted Insufficient resources are available to perform the operation. [EDQUOT, ENOSPC, ENOMEM, EMLINK]
• UnsatisfiedConstraints Implementation-dependent constraints are not satisfied. [EBUSY]
• UnsupportedOperation The implementation does not support renaming in this situation. [EXDEV]
• InappropriateType Either path refers to an existing directory. [ENOTDIR, EISDIR, EINVAL, EEXIST, ENOTEMPTY]

copyFile old new copies the existing file from old to new. If the new file already exists, it is atomically replaced by the old file. Neither path may refer to an existing directory. The permissions of old are copied to new, if possible.

Given an executable file name, search for such file in the directories listed in system PATH. The returned value is the path to the found executable or Nothing if an executable with the given name was not found. For example (findExecutable "ghc") gives you the path to GHC.

The path returned by findExecutable corresponds to the program that would be executed by createProcess when passed the same string (as a RawCommand, not a ShellCommand).

On Windows, findExecutable calls the Win32 function SearchPath, which may search other places before checking the directories in PATH. Where it actually searches depends on registry settings, but notably includes the directory containing the current executable. See http://msdn.microsoft.com/en-us/library/aa365527.aspx for more details.

Search through the given set of directories for the given file.

Search through the given set of directories for the given file and return a list of paths where the given file exists.

Search through the given set of directories for the given file and with the given property (usually permissions) and return a list of paths where the given file exists and has the property.

Create a file symbolic link. The target path can be either absolute or relative and need not refer to an existing file. The order of arguments follows the POSIX convention.

To remove an existing file symbolic link, use removeFile.

Although the distinction between file symbolic links and directory symbolic links does not exist on POSIX systems, on Windows this is an intrinsic property of every symbolic link and cannot be changed without recreating the link. A file symbolic link that actually points to a directory will fail to dereference and vice versa. Moreover, creating symbolic links on Windows may require privileges unavailable to users outside the Administrators group. Portable programs that use symbolic links should take both into consideration.

On Windows, the function is implemented using CreateSymbolicLink. Since 1.3.3.0, the SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE flag is included if supported by the operating system. On POSIX, the function uses symlink and is therefore atomic.

Windows-specific errors: This operation may fail with permissionErrorType if the user lacks the privileges to create symbolic links. It may also fail with illegalOperationErrorType if the file system does not support symbolic links.

Since: 1.5.0

Create a directory symbolic link. The target path can be either absolute or relative and need not refer to an existing directory. The order of arguments follows the POSIX convention.

To remove an existing directory symbolic link, use removeDirLink.

Although the distinction between file symbolic links and directory symbolic links does not exist on POSIX systems, on Windows this is an intrinsic property of every symbolic link and cannot be changed without recreating the link. A file symbolic link that actually points to a directory will fail to dereference and vice versa. Moreover, creating symbolic links on Windows may require privileges unavailable to users outside the Administrators group. Portable programs that use symbolic links should take both into consideration.

On Windows, the function is implemented using CreateSymbolicLink with SYMBOLIC_LINK_FLAG_DIRECTORY. Since 1.3.3.0, the SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE flag is also included if supported by the operating system. On POSIX, this is an alias for createFileLink and is therefore atomic.

Windows-specific errors: This operation may fail with permissionErrorType if the user lacks the privileges to create symbolic links. It may also fail with illegalOperationErrorType if the file system does not support symbolic links.

Since: 1.5.0

Remove an existing directory symbolic link.

On Windows, this is an alias for removeDir. On POSIX systems, this is an alias for removeFile.

See also: removeFile, which can remove an existing file symbolic link.

Since: 1.5.0

Retrieve the target path of either a file or directory symbolic link. The returned path may not exist, and may not even be a valid path.

On Windows systems, this calls DeviceIoControl with FSCTL_GET_REPARSE_POINT. In addition to symbolic links, the function also works on junction points. On POSIX systems, this calls readlink.

Windows-specific errors: This operation may fail with illegalOperationErrorType if the file system does not support symbolic links.

Since: 1.5.0

Check whether the path refers to a symbolic link. An exception is thrown if the path does not exist or is inaccessible.

On Windows, this checks for FILE_ATTRIBUTE_REPARSE_POINT. In addition to symbolic links, the function also returns true on junction points. On POSIX systems, this checks for S_IFLNK.

Check if the given path is a symbolic link.

Since: 1.3.0

Use a temporary file that doesn't already exist.

Creates a new temporary file inside the given directory, making use of the template. The temporary file is deleted after use.

Since: 0.2.0

Create and use a temporary directory.

Creates a new temporary directory inside the given directory, making use of the template. The temporary directory is deleted after use.

Since: 0.2.0

Create and use a temporary file in the system standard temporary directory.

Behaves exactly the same as withTempFile, except that the parent temporary directory will be that returned by getTempDir.

Since: 0.2.0

Create and use a temporary directory in the system standard temporary directory.

Behaves exactly the same as withTempDir, except that the parent temporary directory will be that returned by getTempDir.

Since: 0.2.0

The function creates a temporary file in rw mode. The created file isn't deleted automatically, so you need to delete it manually.

The file is created with permissions such that only the current user can read/write it.

With some exceptions (see below), the file will be created securely in the sense that an attacker should not be able to cause openTempFile to overwrite another file on the filesystem using your credentials, by putting symbolic links (on Unix) in the place where the temporary file is to be created. On Unix the O_CREAT and O_EXCL flags are used to prevent this attack, but note that O_EXCL is sometimes not supported on NFS filesystems, so if you rely on this behaviour it is best to use local filesystems only.

Since: 0.2.0

Like openTempFile, but opens the file in binary mode. On Windows, reading a file in text mode (which is the default) will translate CRLF to LF, and writing will translate LF to CRLF. This is usually what you want with text files. With binary files this is undesirable; also, as usual under Microsoft operating systems, text mode treats control-Z as EOF. Binary mode turns off all special treatment of end-of-line and end-of-file characters.

Since: 0.2.0

Create a temporary directory. The created directory isn't deleted automatically, so you need to delete it manually.

The directory is created with permissions such that only the current user can read/write it.

Since: 0.2.0

The operation doesFileExist returns True if the argument file exists and is not a directory, and False otherwise.

The operation doesDirExist returns True if the argument file exists and is either a directory or a symbolic link to a directory, and False otherwise.

Check if there is a file or directory on specified path.

If argument of the function throws a doesNotExistErrorType, Nothing is returned (other exceptions propagate). Otherwise the result is returned inside a Just.

Since: 0.3.0

The same as forgivingAbsence, but ignores result.

Since: 0.3.1

The getPermissions operation returns the permissions for the file or directory.

The operation may fail with:

• isPermissionError if the user is not permitted to access the permissions; or
• isDoesNotExistError if the file or directory does not exist.

The setPermissions operation sets the permissions for the file or directory.

The operation may fail with:

• isPermissionError if the user is not permitted to set the permissions; or
• isDoesNotExistError if the file or directory does not exist.

Set permissions for the object found on second given path so they match permissions of the object on the first path.

Obtain the time at which the file or directory was last accessed.

The operation may fail with:

• isPermissionError if the user is not permitted to read the access time; or
• isDoesNotExistError if the file or directory does not exist.

Caveat for POSIX systems: This function returns a timestamp with sub-second resolution only if this package is compiled against unix-2.6.0.0 or later and the underlying filesystem supports them.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

Change the time at which the file or directory was last accessed.

The operation may fail with:

• isPermissionError if the user is not permitted to alter the access time; or
• isDoesNotExistError if the file or directory does not exist.

Some caveats for POSIX systems:

• Not all systems support utimensat, in which case the function can only emulate the behavior by reading the modification time and then setting both the access and modification times together. On systems where utimensat is supported, the access time is set atomically with nanosecond precision.
• If compiled against a version of unix prior to 2.7.0.0, the function would not be able to set timestamps with sub-second resolution. In this case, there would also be loss of precision in the modification time.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

Change the time at which the file or directory was last modified.

The operation may fail with:

• isPermissionError if the user is not permitted to alter the modification time; or
• isDoesNotExistError if the file or directory does not exist.

Some caveats for POSIX systems:

• Not all systems support utimensat, in which case the function can only emulate the behavior by reading the access time and then setting both the access and modification times together. On systems where utimensat is supported, the modification time is set atomically with nanosecond precision.
• If compiled against a version of unix prior to 2.7.0.0, the function would not be able to set timestamps with sub-second resolution. In this case, there would also be loss of precision in the access time.

Note: this is a piece of conditional API, only available if directory-1.2.3.0 or later is used.

Obtain the time at which the file or directory was last modified.

The operation may fail with:

• isPermissionError if the user is not permitted to read the modification time; or
• isDoesNotExistError if the file or directory does not exist.

Caveat for POSIX systems: This function returns a timestamp with sub-second resolution only if this package is compiled against unix-2.6.0.0 or later and the underlying filesystem supports them.