path: root/lib/stdlib/doc/src/c.xml

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<erlref>
  <header>
    <copyright>
      <year>1996</year><year>2013</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.
    
    </legalnotice>

    <title>c</title>
    <prepared>Joe Armstrong</prepared>
    <docno>1</docno>
    <date>96-10-30</date>
    <rev>B</rev>
  </header>
  <module>c</module>
  <modulesummary>Command Interface Module</modulesummary>
  <description>
    <p>The <c>c</c> module enables users to enter the short form of
      some commonly used commands.</p>
    <note>
      <p>These functions are are intended for interactive use in
        the Erlang shell only. The module prefix may be omitted.</p>
    </note>
  </description>
  <funcs>
    <func>
      <name name="bt" arity="1"/>
      <fsummary>Stack backtrace for a process</fsummary>
      <desc>
        <p>Stack backtrace for a process. Equivalent to
          <c>erlang:process_display(<anno>Pid</anno>, backtrace)</c>.</p>
      </desc>
    </func>
    <func>
      <name name="c" arity="1"/>
      <name name="c" arity="2"/>
      <fsummary>Compile and load code in a file</fsummary>
      <desc>
        <p><c>c/1,2</c> compiles and then purges and loads the code for
          a file. <c><anno>Options</anno></c> defaults to []. Compilation is
          equivalent to:</p>
        <code type="none">
compile:file(<anno>File</anno>, <anno>Options</anno> ++ [report_errors, report_warnings])</code>
        <p>Note that purging the code means that any processes
          lingering in old code for the module are killed without
          warning. See <c>code/3</c> for more information.</p>
      </desc>
    </func>
    <func>
      <name name="cd" arity="1"/>
      <fsummary>Change working directory</fsummary>
      <desc>
        <p>Changes working directory to <c><anno>Dir</anno></c>, which may be a
          relative name, and then prints the name of the new working
          directory.</p>
        <pre>
2> <input>cd("../erlang").</input>
/home/ron/erlang</pre>
      </desc>
    </func>
    <func>
      <name name="flush" arity="0"/>
      <fsummary>Flush any messages sent to the shell</fsummary>
      <desc>
        <p>Flushes any messages sent to the shell.</p>
      </desc>
    </func>
    <func>
      <name name="help" arity="0"/>
      <fsummary>Help information</fsummary>
      <desc>
        <p>Displays help information: all valid shell internal commands,
          and commands in this module.</p>
      </desc>
    </func>
    <func>
      <name name="i" arity="0"/>
      <name name="ni" arity="0"/>
      <fsummary>Information about the system</fsummary>
      <desc>
        <p><c>i/0</c> displays information about the system, listing
          information about all processes. <c>ni/0</c> does the same,
          but for all nodes the network.</p>
      </desc>
    </func>
    <func>
      <name name="i" arity="3"/>
      <fsummary>Information about pid &lt;X.Y.Z&gt;</fsummary>
      <desc>
        <p>Displays information about a process, Equivalent to
          <c>process_info(pid(<anno>X</anno>, <anno>Y</anno>, <anno>Z</anno>))</c>, but location transparent.</p>
      </desc>
    </func>
    <func>
      <name name="l" arity="1"/>
      <fsummary>Load or reload module</fsummary>
      <desc>
        <p>Purges and loads, or reloads, a module by calling
          <c>code:purge(<anno>Module</anno>)</c> followed by
          <c>code:load_file(<anno>Module</anno>)</c>.</p>
        <p>Note that purging the code means that any processes
          lingering in old code for the module are killed without
          warning. See <c>code/3</c> for more information.</p>
      </desc>
    </func>
    <func>
      <name>lc(Files) -> ok</name>
      <fsummary>Compile a list of files</fsummary>
      <type>
        <v>Files = [File]</v>
        <v>File = <seealso marker="file#type-filename">file:filename()
          </seealso></v>
      </type>
      <desc>
        <p>Compiles a list of files by calling <c>compile:file(File, [report_errors, report_warnings])</c> for each <c>File</c>
          in <c>Files</c>.</p>
      </desc>
    </func>
    <func>
      <name name="ls" arity="0"/>
      <fsummary>List files in the current directory</fsummary>
      <desc>
        <p>Lists files in the current directory.</p>
      </desc>
    </func>
    <func>
      <name name="ls" arity="1"/>
      <fsummary>List files in a directory or a single file</fsummary>
      <desc>
        <p>Lists files in directory <c><anno>Dir</anno></c> or, if Dir is a file, only list it.</p>
      </desc>
    </func>
    <func>
      <name name="m" arity="0"/>
      <fsummary>Which modules are loaded</fsummary>
      <desc>
        <p>Displays information about the loaded modules, including
          the files from which they have been loaded.</p>
      </desc>
    </func>
    <func>
      <name name="m" arity="1"/>
      <fsummary>Information about a module</fsummary>
      <desc>
        <p>Displays information about <c><anno>Module</anno></c>.</p>
      </desc>
    </func>
    <func>
      <name name="memory" arity="0"/>
      <fsummary>Memory allocation information</fsummary>
      <desc>
        <p>Memory allocation information. Equivalent to
          <seealso marker="erts:erlang#memory/0"><c>erlang:memory/0</c>
          </seealso>.</p>
      </desc>
    </func>
    <func>
      <name name="memory" arity="1" clause_i="1"/>
      <name name="memory" arity="1" clause_i="2"/>
      <fsummary>Memory allocation information</fsummary>
      <desc>
        <p>Memory allocation information. Equivalent to
          <seealso marker="erts:erlang#memory/1"><c>erlang:memory/1</c>
          </seealso>.</p>
      </desc>
    </func>
    <func>
      <name name="nc" arity="1"/>
      <name name="nc" arity="2"/>
      <fsummary>Compile and load code in a file on all nodes</fsummary>
      <desc>
        <p>Compiles and then loads the code for a file on all nodes.
          <c><anno>Options</anno></c> defaults to []. Compilation is equivalent to:</p>
        <code type="none">
compile:file(<anno>File</anno>, <anno>Options</anno> ++ [report_errors, report_warnings])</code>
      </desc>
    </func>
    <func>
      <name name="nl" arity="1"/>
      <fsummary>Load module on all nodes</fsummary>
      <desc>
        <p>Loads <c><anno>Module</anno></c> on all nodes.</p>
      </desc>
    </func>
    <func>
      <name name="pid" arity="3"/>
      <fsummary>Convert X,Y,Z to a pid</fsummary>
      <desc>
        <p>Converts <c><anno>X</anno></c>, <c><anno>Y</anno></c>, <c><anno>Z</anno></c> to the pid
          <c><![CDATA[<X.Y.Z>]]></c>. This function should only be used when
          debugging.</p>
      </desc>
    </func>
    <func>
      <name name="pwd" arity="0"/>
      <fsummary>Print working directory</fsummary>
      <desc>
        <p>Prints the name of the working directory.</p>
      </desc>
    </func>
    <func>
      <name name="q" arity="0"/>
      <fsummary>Quit - shorthand for <c>init:stop()</c></fsummary>
      <desc>
        <p>This function is shorthand for <c>init:stop()</c>, that is,
          it causes the node to stop in a controlled fashion.</p>
      </desc>
    </func>
    <func>
      <name name="regs" arity="0"/>
      <name name="nregs" arity="0"/>
      <fsummary>Information about registered processes</fsummary>
      <desc>
        <p><c>regs/0</c> displays information about all registered
          processes. <c>nregs/0</c> does the same, but for all nodes
          in the network.</p>
      </desc>
    </func>
    <func>
      <name name="uptime" arity="0"/>
      <fsummary>Print node uptime</fsummary>
      <desc>
        <p>Prints the node uptime (as given by
           <c>erlang:statistics(wall_clock)</c>), in human-readable form.</p>
      </desc>
    </func>
    <func>
      <name>xm(ModSpec) -> void()</name>
      <fsummary>Cross reference check a module</fsummary>
      <type>
        <v>ModSpec = Module | Filename</v>
        <v>&nbsp;Module = atom()</v>
        <v>&nbsp;Filename = string()</v>
      </type>
      <desc>
        <p>This function finds undefined functions, unused functions,
          and calls to deprecated functions in a module by calling
          <c>xref:m/1</c>.</p>
      </desc>
    </func>
    <func>
      <name>y(File) -> YeccRet</name>
      <fsummary>Generate an LALR-1 parser</fsummary>
      <type>
        <v>File = name() -- see filename(3)</v>
        <v>YeccRet = -- see yecc:file/2</v>
      </type>
      <desc>
        <p>Generates an LALR-1 parser. Equivalent to:</p>
        <code type="none">
yecc:file(File)</code>
      </desc>
    </func>
    <func>
      <name>y(File, Options) -> YeccRet</name>
      <fsummary>Generate an LALR-1 parser</fsummary>
      <type>
        <v>File = name() -- see filename(3)</v>
        <v>Options, YeccRet = -- see yecc:file/2</v>
      </type>
      <desc>
        <p>Generates an LALR-1 parser. Equivalent to:</p>
        <code type="none">
yecc:file(File, Options)</code>
      </desc>
    </func>
  </funcs>

  <section>
    <title>See Also</title>
    <p><seealso marker="compiler:compile">compile(3)</seealso>,
      <seealso marker="filename">filename(3)</seealso>, 
      <seealso marker="erts:erlang">erlang(3)</seealso>, 
      <seealso marker="parsetools:yecc">yecc(3)</seealso>,
      <seealso marker="tools:xref">xref(3)</seealso></p>
  </section>
</erlref>