1filelib(3) Erlang Module Definition filelib(3)
2
6 filelib - File utilities, such as wildcard matching of filenames.
7
10 This module contains utilities on a higher level than the file module.
11 This module does not support "raw" filenames (that is, files whose
13 names do not comply with the expected encoding). Such files are ignored
14 by the functions in this module.
15 For more information about raw filenames, see the file module.
17 Note:
19 Functionality in this module generally assumes valid input and does not
20 necessarily fail on input that does not use a valid encoding, but may
21 instead very likely produce invalid output.
22 File operations used to accept filenames containing null characters
24 (integer value zero). This caused the name to be truncated and in some
25 cases arguments to primitive operations to be mixed up. Filenames con‐
26 taining null characters inside the filename are now rejected and will
27 cause primitive file operations to fail.
28 Warning:
31 Currently null characters at the end of the filename will be accepted
32 by primitive file operations. Such filenames are however still docu‐
33 mented as invalid. The implementation will also change in the future
34 and reject such filenames.
35
38 filename() = file:name()
39 dirname() = filename()
41 dirname_all() = filename_all()
43 filename_all() = file:name_all()
45 find_file_rule() =
47 {ObjDirSuffix :: string(), SrcDirSuffix :: string()}
48 find_source_rule() =
50 {ObjExtension :: string(),
51 SrcExtension :: string(),
52 [find_file_rule()]}
53
55 ensure_dir(Name) -> ok | {error, Reason}
56 Types:
58 Name = filename_all() | dirname_all()
60 Reason = file:posix()
61 Ensures that all parent directories for the specified file or
63 directory name Name exist, trying to create them if necessary.
64 Returns ok if all parent directories already exist or can be
66 created. Returns {error, Reason} if some parent directory does
67 not exist and cannot be created.
68 file_size(Filename) -> integer() >= 0
70 Types:
72 Filename = filename_all()
74 Returns the size of the specified file.
76 fold_files(Dir, RegExp, Recursive, Fun, AccIn) -> AccOut
78 Types:
80 Dir = dirname()
82 RegExp = string()
83 Recursive = boolean()
84 Fun = fun((F :: file:filename(), AccIn) -> AccOut)
85 AccIn = AccOut = term()
86 Folds function Fun over all (regular) files F in directory Dir
88 that match the regular expression RegExp (for a description of
89 the allowed regular expressions, see the re module). If Recur‐
90 sive is true, all subdirectories to Dir are processed. The regu‐
91 lar expression matching is only done on the filename without the
92 directory part.
93 If Unicode filename translation is in effect and the file system
95 is transparent, filenames that cannot be interpreted as Unicode
96 can be encountered, in which case the fun() must be prepared to
97 handle raw filenames (that is, binaries). If the regular expres‐
98 sion contains codepoints > 255, it does not match filenames that
99 do not conform to the expected character encoding (that is, are
100 not encoded in valid UTF-8).
101 For more information about raw filenames, see the file module.
103 is_dir(Name) -> boolean()
105 Types:
107 Name = filename_all() | dirname_all()
109 Returns true if Name refers to a directory, otherwise false.
111 is_file(Name) -> boolean()
113 Types:
115 Name = filename_all() | dirname_all()
117 Returns true if Name refers to a file or a directory, otherwise
119 false.
120 is_regular(Name) -> boolean()
122 Types:
124 Name = filename_all()
126 Returns true if Name refers to a (regular) file, otherwise
128 false.
129 last_modified(Name) -> file:date_time() | 0
131 Types:
133 Name = filename_all() | dirname_all()
135 Returns the date and time the specified file or directory was
137 last modified, or 0 if the file does not exist.
138 wildcard(Wildcard) -> [file:filename()]
140 Types:
142 Wildcard = filename() | dirname()
144 Returns a list of all files that match Unix-style wildcard
146 string Wildcard.
147 The wildcard string looks like an ordinary filename, except that
149 the following "wildcard characters" are interpreted in a special
150 way:
151 ?:
153 Matches one character.
154 *:
156 Matches any number of characters up to the end of the file‐
157 name, the next dot, or the next slash.
158 **:
160 Two adjacent * used as a single pattern match all files and
161 zero or more directories and subdirectories.
162 [Character1,Character2,...]:
164 Matches any of the characters listed. Two characters sepa‐
165 rated by a hyphen match a range of characters. Example: [A-
166 Z] matches any uppercase letter.
167 {Item,...}:
169 Alternation. Matches one of the alternatives.
170 Other characters represent themselves. Only filenames that have
172 exactly the same character in the same position match. Matching
173 is case-sensitive, for example, "a" does not match "A".
174 Directory separators must always be written as /, even on Win‐
176 dows.
177 A character preceded by \ loses its special meaning. Note that \
179 must be written as \\ in a string literal. For example, "\\?*"
180 will match any filename starting with ?.
181 Notice that multiple "*" characters are allowed (as in Unix
183 wildcards, but opposed to Windows/DOS wildcards).
184 Examples:
186 The following examples assume that the current directory is the
188 top of an Erlang/OTP installation.
189 To find all .beam files in all applications, use the following
191 line:
192 filelib:wildcard("lib/*/ebin/*.beam").
194 To find .erl or .hrl in all applications src directories, use
196 either of the following lines:
197 filelib:wildcard("lib/*/src/*.?rl")
199 filelib:wildcard("lib/*/src/*.{erl,hrl}")
201 To find all .hrl files in src or include directories:
203 filelib:wildcard("lib/*/{src,include}/*.hrl").
205 To find all .erl or .hrl files in either src or include directo‐
207 ries:
208 filelib:wildcard("lib/*/{src,include}/*.{erl,hrl}")
210 To find all .erl or .hrl files in any subdirectory:
212 filelib:wildcard("lib/**/*.{erl,hrl}")
214 wildcard(Wildcard, Cwd) -> [file:filename()]
216 Types:
218 Wildcard = filename() | dirname()
220 Cwd = dirname()
221 Same as wildcard/1, except that Cwd is used instead of the work‐
223 ing directory.
224 find_file(Filename :: filename(), Dir :: filename()) ->
226 {ok, filename()} | {error, not_found}
227 find_file(Filename :: filename(),
229 Dir :: filename(),
230 Rules :: [find_file_rule()]) ->
231 {ok, filename()} | {error, not_found}
232 Looks for a file of the given name by applying suffix rules to
234 the given directory path. For example, a rule {"ebin", "src"}
235 means that if the directory path ends with "ebin", the corre‐
236 sponding path ending in "src" should be searched.
237 If Rules is left out or is an empty list, the default system
239 rules are used. See also the Kernel application parameter
240 source_search_rules.
241 find_source(FilePath :: filename()) ->
243 {ok, filename()} | {error, not_found}
244 Equivalent to find_source(Base, Dir), where Dir is file‐
246 name:dirname(FilePath) and Base is filename:basename(FilePath).
247 find_source(Filename :: filename(), Dir :: filename()) ->
249 {ok, filename()} | {error, not_found}
250 find_source(Filename :: filename(),
252 Dir :: filename(),
253 Rules :: [find_source_rule()]) ->
254 {ok, filename()} | {error, not_found}
255 Applies file extension specific rules to find the source file
257 for a given object file relative to the object directory. For
258 example, for a file with the extension .beam, the default rule
259 is to look for a file with a corresponding extension .erl by
260 replacing the suffix "ebin" of the object directory path with
261 "src" or "src/*". The file search is done through find_file/3.
262 The directory of the object file is always tried before any
263 other directory specified by the rules.
264 If Rules is left out or is an empty list, the default system
266 rules are used. See also the Kernel application parameter
267 source_search_rules.
268 safe_relative_path(Filename, Cwd) -> unsafe | SafeFilename
270 Types:
272 Filename = Cwd = SafeFilename = filename_all()
274 Sanitizes the relative path by eliminating ".." and "." compo‐
276 nents to protect against directory traversal attacks. Either
277 returns the sanitized path name, or the atom unsafe if the path
278 is unsafe. The path is considered unsafe in the following cir‐
279 cumstances:
280 * The path is not relative.
282 * A ".." component would climb up above the root of the rela‐
284 tive path.
285 * A symbolic link in the path points above the root of the
287 relative path.
288 Examples:
290 1> {ok, Cwd} = file:get_cwd().
292 2> filelib:safe_relative_path("dir/sub_dir/..", Cwd).
293 "dir"
294 3> filelib:safe_relative_path("dir/..", Cwd).
295 []
296 4> filelib:safe_relative_path("dir/../..", Cwd).
297 unsafe
298 5> filelib:safe_relative_path("/abs/path", Cwd).
299 unsafe
300Ericsson AB stdlib 3.14.1 filelib(3)