filelib
File utilities, such as wildcard matching of filenames
This module contains utilities on a higher level than the file
module.
The module supports Unicode file names, so that it will match against regular expressions given in Unicode and that it will find and process raw file names (i.e. files named in a way that does not confirm to the expected encoding).
If the VM operates in Unicode file naming mode on a machine with transparent file naming, the fun()
provided to fold_files/5
needs to be prepared to handle binary file names.
For more information about raw file names, see the file module.
Functions
ensure_dir(Name) -> ok | {error, Reason}
Name = filename() | dirname()
Reason = file:posix()
The ensure_dir/1
function ensures that all parent
directories for the given file or directory name
exist, trying to create them if necessary.
Returns ok
if all parent directories already exist
or could be created, or {error,
if some parent
directory does not exist and could not be created for some
reason.
file_size(Filename) -> integer() >= 0
Filename = filename()
The file_size
function returns the size of the given file.
fold_files(Dir, RegExp, Recursive, Fun, AccIn) -> AccOut
Dir = dirname()
RegExp = string()
Recursive = boolean()
Fun = fun((F :: file:filename(), AccIn) -> AccOut)
AccIn = AccOut = term()
The fold_files/5
function folds the function
over all (regular) files
in the
directory
that match the regular expression
(see the re module for a description
of the allowed regular expressions).
If
is true all sub-directories to Dir
are processed. The regular expression matching is done on just
the filename without the directory part.
If Unicode file name translation is in effect and the file
system is completely transparent, file names that cannot be
interpreted as Unicode may be encountered, in which case the
fun()
must be prepared to handle raw file names
(i.e. binaries). If the regular expression contains
codepoints beyond 255, it will not match file names that do
not conform to the expected character encoding (i.e. are not
encoded in valid UTF-8).
For more information about raw file names, see the file module.
is_dir(Name) -> boolean()
Name = filename() | dirname()
The is_dir/1
function returns true
if
refers to a directory, and false
otherwise.
is_file(Name) -> boolean()
Name = filename() | dirname()
The is_file/1
function returns true
if
refers to a file or a directory, and false
otherwise.
is_regular(Name) -> boolean()
Name = filename()
The is_regular/1
function returns true
if
refers to a file (regular file), and false
otherwise.
last_modified(Name) -> file:date_time() | 0
Name = filename() | dirname()
The last_modified/1
function returns the date and time the
given file or directory was last modified, or 0 if the file
does not exist.
wildcard(Wildcard) -> [file:filename()]
Wildcard = filename() | dirname()
The wildcard/1
function returns a list of all files
that match Unix-style wildcard-string
.
The wildcard string looks like an ordinary filename, except that certain "wildcard characters" are interpreted in a special way. The following characters are special:
Matches one character.
Matches any number of characters up to the end of the filename, the next dot, or the next slash.
Two adjacent *
's used as a single pattern will
match all files and zero or more directories and subdirectories.
Matches any of the characters listed. Two characters
separated by a hyphen will match a range of characters.
Example: [A-Z]
will match any uppercase letter.
Alternation. Matches one of the alternatives.
Other characters represent themselves. Only filenames that have exactly the same character in the same position will match. (Matching is case-sensitive; i.e. "a" will not match "A").
Note that multiple "*" characters are allowed (as in Unix wildcards, but opposed to Windows/DOS wildcards).
Examples:
The following examples assume that the current directory is the top of an Erlang/OTP installation.
To find all .beam
files in all applications, the following
line can be used:
filelib:wildcard("lib/*/ebin/*.beam").
To find either .erl
or .hrl
in all applications
src
directories, the following
filelib:wildcard("lib/*/src/*.?rl")
or the following line
filelib:wildcard("lib/*/src/*.{erl,hrl}")
can be used.
To find all .hrl
files in either src
or include
directories, use:
filelib:wildcard("lib/*/{src,include}/*.hrl").
To find all .erl
or .hrl
files in either
src
or include
directories, use:
filelib:wildcard("lib/*/{src,include}/*.{erl,hrl}")
To find all .erl
or .hrl
files in any
subdirectory, use:
filelib:wildcard("lib/**/*.{erl,hrl}")
wildcard(Wildcard, Cwd) -> [file:filename()]
Wildcard = filename() | dirname()
Cwd = dirname()
The wildcard/2
function works like wildcard/1
,
except that instead of the actual working directory,
will be used.