File utilities, such as wildcard matching of filenames.
This module contains utilities on a higher level than the
file
module.
This module does not support "raw" filenames (that is, files whose names do not comply with the expected encoding). Such files are ignored by the functions in this module.
For more information about raw filenames, see the
file
module.
Note!
Functionality in this module generally assumes valid input and does not necessarily fail on input that does not use a valid encoding, but may instead very likely produce invalid output.
File operations used to accept filenames containing null characters (integer value zero). This caused the name to be truncated and in some cases arguments to primitive operations to be mixed up. Filenames containing null characters inside the filename are now rejected and will cause primitive file operations to fail.
Warning!
Currently null characters at the end of the filename will be accepted by primitive file operations. Such filenames are however still documented as invalid. The implementation will also change in the future and reject such filenames.
Types
filename() = file:name()
dirname() = filename()
dirname_all() = filename_all()
filename_all() = file:name_all()
find_file_rule() =
{ObjDirSuffix :: string(), SrcDirSuffix :: string()}
find_source_rule() =
{ObjExtension :: string(),
SrcExtension :: string(),
[find_file_rule()]}
Functions
ensure_dir(Name) -> ok | {error, Reason}
Name = filename_all() | dirname_all()
Reason = file:posix()
Ensures that all parent directories for the specified file or
directory name
exist, trying to create them if necessary.
Returns ok
if all parent directories already exist
or can be created. Returns {error,
if
some parent directory does not exist and cannot be created.
file_size(Filename) -> integer() >= 0
Filename = filename_all()
Returns the size of the specified 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()
Folds function
over all (regular) files
in directory
that match
the regular expression
(for a description
of the allowed regular expressions,
see the re
module).
If
is true
, all subdirectories
to Dir
are processed. The regular expression matching is only done on
the filename without the directory part.
If Unicode filename translation is in effect and the file
system is transparent, filenames that cannot be
interpreted as Unicode can be encountered, in which case the
fun()
must be prepared to handle raw filenames
(that is, binaries). If the regular expression contains
codepoints > 255, it does not match filenames that do
not conform to the expected character encoding (that is, are not
encoded in valid UTF-8).
For more information about raw filenames, see the
file
module.
is_dir(Name) -> boolean()
Name = filename_all() | dirname_all()
Returns true
if
refers to a directory, otherwise false
.
is_file(Name) -> boolean()
Name = filename_all() | dirname_all()
Returns true
if
refers to a file or a directory, otherwise false
.
is_regular(Name) -> boolean()
Name = filename_all()
Returns true
if
refers to a (regular) file, otherwise false
.
last_modified(Name) -> file:date_time() | 0
Name = filename_all() | dirname_all()
Returns the date and time the specified file or directory was last
modified, or 0
if the file does not exist.
wildcard(Wildcard) -> [file:filename()]
Wildcard = filename() | dirname()
Returns a list of all files that match Unix-style wildcard string
.
The wildcard string looks like an ordinary filename, except that the following "wildcard characters" are interpreted in a special way:
Matches one character.
Matches any number of characters up to the end of the filename, the next dot, or the next slash.
Two adjacent *
used as a single pattern match
all files and zero or more directories and subdirectories.
Matches any of the characters listed. Two characters
separated by a hyphen match a range of characters.
Example: [A-Z]
matches 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 match. Matching is case-sensitive, for example, "a" does not match "A".
Directory separators must always be written as /
, even on
Windows.
A character preceded by \
loses its special meaning. Note
that \
must be written as \\
in a string literal.
For example, "\\?*" will match any filename starting with ?
.
Notice 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, use the
following line:
filelib:wildcard("lib/*/ebin/*.beam").
To find .erl
or .hrl
in all applications src
directories, use either of the following lines:
filelib:wildcard("lib/*/src/*.?rl")
filelib:wildcard("lib/*/src/*.{erl,hrl}")
To find all .hrl
files in src
or include
directories:
filelib:wildcard("lib/*/{src,include}/*.hrl").
To find all .erl
or .hrl
files in either
src
or include
directories:
filelib:wildcard("lib/*/{src,include}/*.{erl,hrl}")
To find all .erl
or .hrl
files in any subdirectory:
filelib:wildcard("lib/**/*.{erl,hrl}")
wildcard(Wildcard, Cwd) -> [file:filename()]
Wildcard = filename() | dirname()
Cwd = dirname()
Same as wildcard/1
,
except that
is used instead of the working
directory.
find_file(Filename :: filename(), Dir :: filename()) ->
{ok, filename()} | {error, not_found}
find_file(Filename :: filename(),
Dir :: filename(),
Rules :: [find_file_rule()]) ->
{ok, filename()} | {error, not_found}
Looks for a file of the given name by applying suffix rules to
the given directory path. For example, a rule {"ebin", "src"}
means that if the directory path ends with "ebin"
, the
corresponding path ending in "src"
should be searched.
If
is left out or is an empty list, the
default system rules are used. See also the Kernel application
parameter source_search_rules
.
find_source(FilePath :: filename()) ->
{ok, filename()} | {error, not_found}
Equivalent to find_source(Base, Dir)
, where Dir
is
filename:dirname(
and Base
is
filename:basename(
.
find_source(Filename :: filename(), Dir :: filename()) ->
{ok, filename()} | {error, not_found}
find_source(Filename :: filename(),
Dir :: filename(),
Rules :: [find_source_rule()]) ->
{ok, filename()} | {error, not_found}
Applies file extension specific rules to find the source file for
a given object file relative to the object directory. For example,
for a file with the extension .beam
, the default rule is to
look for a file with a corresponding extension .erl
by
replacing the suffix "ebin"
of the object directory path with
"src"
or "src/*"
.
The file search is done through find_file/3
. The directory of
the object file is always tried before any other directory specified
by the rules.
If
is left out or is an empty list, the
default system rules are used. See also the Kernel application
parameter source_search_rules
.