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<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
<year>2003</year><year>2013</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
</legalnotice>
<title>filelib</title>
<prepared>Bjorn Gustavsson</prepared>
<responsible>Bjorn Gustavsson</responsible>
<docno>1</docno>
<approved>Kenneth Lundin</approved>
<checked></checked>
<date>03-01-21</date>
<rev>A</rev>
<file>filelib.sgml</file>
</header>
<module>filelib</module>
<modulesummary>File utilities, such as wildcard matching of filenames</modulesummary>
<description>
<p>This module contains utilities on a higher level than the <c>file</c>
module.</p>
<p>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).</p>
<p>If the VM operates in Unicode file naming mode on a machine with transparent file naming, the <c>fun()</c> provided to <c>fold_files/5</c> needs to be prepared to handle binary file names.</p>
<p>For more information about raw file names, see the <seealso marker="kernel:file">file</seealso> module.</p>
</description>
<datatypes>
<datatype>
<name name="filename"/>
</datatype>
<datatype>
<name name="dirname"/>
</datatype>
</datatypes>
<funcs>
<func>
<name name="ensure_dir" arity="1"/>
<fsummary>Ensure that all parent directories for a file or directory exist.</fsummary>
<desc>
<p>The <c>ensure_dir/1</c> function ensures that all parent
directories for the given file or directory name <c><anno>Name</anno></c>
exist, trying to create them if necessary.</p>
<p>Returns <c>ok</c> if all parent directories already exist
or could be created, or <c>{error, <anno>Reason</anno>}</c> if some parent
directory does not exist and could not be created for some
reason.</p>
</desc>
</func>
<func>
<name name="file_size" arity="1"/>
<fsummary>Return the size in bytes of the file.</fsummary>
<desc>
<p>The <c>file_size</c> function returns the size of the given file.</p>
</desc>
</func>
<func>
<name name="fold_files" arity="5"/>
<fsummary>Fold over all files matching a regular expression.</fsummary>
<desc>
<p>The <c>fold_files/5</c> function folds the function
<c><anno>Fun</anno></c> over all (regular) files <c><anno>F</anno></c> in the
directory <c><anno>Dir</anno></c> that match the regular expression <c><anno>RegExp</anno></c>
(see the <seealso marker="re">re</seealso> module for a description
of the allowed regular expressions).
If <c><anno>Recursive</anno></c> is true all sub-directories to <c>Dir</c>
are processed. The regular expression matching is done on just
the filename without the directory part.</p>
<p>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
<c>fun()</c> 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).</p>
<p>For more information about raw file names, see the
<seealso marker="kernel:file">file</seealso> module.</p>
</desc>
</func>
<func>
<name name="is_dir" arity="1"/>
<fsummary>Test whether Name refer to a directory or not</fsummary>
<desc>
<p>The <c>is_dir/1</c> function returns <c>true</c> if <c><anno>Name</anno></c>
refers to a directory, and <c>false</c> otherwise.</p>
</desc>
</func>
<func>
<name name="is_file" arity="1"/>
<fsummary>Test whether Name refer to a file or directory.</fsummary>
<desc>
<p>The <c>is_file/1</c> function returns <c>true</c> if <c><anno>Name</anno></c>
refers to a file or a directory, and <c>false</c> otherwise.</p>
</desc>
</func>
<func>
<name name="is_regular" arity="1"/>
<fsummary>Test whether Name refer to a (regular) file.</fsummary>
<desc>
<p>The <c>is_regular/1</c> function returns <c>true</c> if <c><anno>Name</anno></c>
refers to a file (regular file), and <c>false</c> otherwise.</p>
</desc>
</func>
<func>
<name name="last_modified" arity="1"/>
<fsummary>Return the local date and time when a file was last modified.</fsummary>
<desc>
<p>The <c>last_modified/1</c> function returns the date and time the
given file or directory was last modified, or 0 if the file
does not exist.</p>
</desc>
</func>
<func>
<name name="wildcard" arity="1"/>
<fsummary>Match filenames using Unix-style wildcards.</fsummary>
<desc>
<p>The <c>wildcard/1</c> function returns a list of all files
that match Unix-style wildcard-string <c><anno>Wildcard</anno></c>.</p>
<p>The wildcard string looks like an ordinary filename, except
that certain "wildcard characters" are interpreted in a special
way. The following characters are special:
</p>
<taglist>
<tag>?</tag>
<item>
<p>Matches one character.</p>
</item>
<tag>*</tag>
<item>
<p>Matches any number of characters up to the end of
the filename, the next dot, or the next slash.</p>
</item>
<tag>**</tag>
<item>
<p>Two adjacent <c>*</c>'s used as a single pattern will
match all files and zero or more directories and subdirectories.</p>
</item>
<tag>[Character1,Character2,...]</tag>
<item>
<p>Matches any of the characters listed. Two characters
separated by a hyphen will match a range of characters.
Example: <c>[A-Z]</c> will match any uppercase letter.</p>
</item>
<tag>{Item,...}</tag>
<item>
<p>Alternation. Matches one of the alternatives.</p>
</item>
</taglist>
<p>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").
</p>
<p>Note that multiple "*" characters are allowed
(as in Unix wildcards, but opposed to Windows/DOS wildcards).
</p>
<p>Examples:</p>
<p>The following examples assume that the current directory is the
top of an Erlang/OTP installation.
</p>
<p>To find all <c>.beam</c> files in all applications, the following
line can be used:</p>
<code type="none">
filelib:wildcard("lib/*/ebin/*.beam"). </code>
<p>To find either <c>.erl</c> or <c>.hrl</c> in all applications
<c>src</c> directories, the following</p>
<code type="none">
filelib:wildcard("lib/*/src/*.?rl") </code>
<p>or the following line</p>
<code type="none">
filelib:wildcard("lib/*/src/*.{erl,hrl}") </code>
<p>can be used.</p>
<p>To find all <c>.hrl</c> files in either <c>src</c> or <c>include</c>
directories, use:</p>
<code type="none">
filelib:wildcard("lib/*/{src,include}/*.hrl"). </code>
<p>To find all <c>.erl</c> or <c>.hrl</c> files in either
<c>src</c> or <c>include</c> directories, use:</p>
<code type="none">
filelib:wildcard("lib/*/{src,include}/*.{erl,hrl}") </code>
<p>To find all <c>.erl</c> or <c>.hrl</c> files in any
subdirectory, use:</p>
<code type="none">
filelib:wildcard("lib/**/*.{erl,hrl}") </code>
</desc>
</func>
<func>
<name name="wildcard" arity="2"/>
<fsummary>Match filenames using Unix-style wildcards starting at a specified directory.</fsummary>
<desc>
<p>The <c>wildcard/2</c> function works like <c>wildcard/1</c>,
except that instead of the actual working directory, <c><anno>Cwd</anno></c>
will be used.</p>
</desc>
</func>
</funcs>
</erlref>
