lfs-book/chapter07/creatingdirs.xml

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<sect1 id="ch-tools-creatingdirs">
  <?dbhtml filename="creatingdirs.html"?>

  <title>Creating Directories</title>

  <para>It is time to create the full structure in the LFS file system.</para>

  <para>Create some root-level directories that are not in the limited set
    required in the previous chapters by issuing the following command:</para>

  <note><para>Some of the directories below have already been created earlier
  with explicit instructions or when installing some packages.  They are
  repeated below for completeness.</para></note>

<screen><userinput>mkdir -pv /{boot,home,mnt,opt,srv}</userinput></screen>

  <para>Create the required set of subdirectories below the root-level by
    issuing the following commands:</para>

<screen><userinput>mkdir -pv /etc/{opt,sysconfig}
mkdir -pv /lib/firmware
mkdir -pv /media/{floppy,cdrom}
mkdir -pv /usr/{,local/}{bin,include,lib,sbin,src}
mkdir -pv /usr/{,local/}share/{color,dict,doc,info,locale,man}
mkdir -pv /usr/{,local/}share/{misc,terminfo,zoneinfo}
mkdir -pv /usr/{,local/}share/man/man{1..8}
mkdir -pv /var/{cache,local,log,mail,opt,spool}
mkdir -pv /var/lib/{color,misc,locate}

ln -sfv /run /var/run
ln -sfv /run/lock /var/lock

install -dv -m 0750 /root
install -dv -m 1777 /tmp /var/tmp</userinput></screen>

  <para>Directories are, by default, created with permission mode 755, but
  this is not desirable for all directories. In the commands above, two
  changes are made&mdash;one to the home directory of user <systemitem
  class="username">root</systemitem>, and another to the directories for
  temporary files.</para>

  <para>The first mode change ensures that not just anybody can enter
  the <filename class="directory">/root</filename> directory&mdash;the
  same as a normal user would do with his or her home directory. The
  second mode change makes sure that any user can write to the
  <filename class="directory">/tmp</filename> and <filename
  class="directory">/var/tmp</filename> directories, but cannot remove
  another user's files from them. The latter is prohibited by the so-called
  <quote>sticky bit,</quote> the highest bit (1) in the 1777 bit mask.</para>

  <sect2>
    <title>FHS Compliance Note</title>

    <para>The directory tree is based on the Filesystem Hierarchy Standard
    (FHS) (available at <ulink
    url="https://refspecs.linuxfoundation.org/fhs.shtml"/>).  The FHS also specifies
    the optional existence of some directories such as <filename
    class="directory">/usr/local/games</filename> and <filename
    class="directory">/usr/share/games</filename>.  We create only the
    directories that are needed. However, feel free to create these
    directories.  </para>

  </sect2>

</sect1>