lfs-book-zh_CN/chapter05/setting-environment.xml

<sect1 id="ch05-settingenviron">
<title>Setting up the environment</title>
<?dbhtml filename="settingenviron.html" dir="chapter05"?>

<para>While logged in as user <emphasis>lfs</emphasis>, issue the
following commands to set up a good work environment:</para>

<para><screen><userinput>cat &gt; ~/.bash_profile &lt;&lt; "EOF"
set +h
umask 022
LFS=/mnt/lfs
LC_ALL=POSIX
LDFLAGS="-s"
PATH=/stage1/bin:$PATH
export LFS LC_ALL LDFLAGS PATH
EOF
source ~/.bash_profile</userinput></screen></para>

<para><userinput>set +h</userinput> turns off Bash's hash function. Hash
normally is a useful feature where Bash uses a hash table to remember the
full pathnames of executable files to avoid multiple `PATH' searches.
However, we'd like the new tools to become available as soon as they are
installed.  By switching off the hash function, our "interactive" commands
(make, patch, sed, cp and so forth) will always use the newest available
during the build process.</para>

<para>This profile sets the umask to 022, so newly created files and
directories will have the correct permissions. To be more specific, only
the file owner will have write permission to new files and directories.
Other users of the system will be have read permission, and executable
permission to directories. It is advisable to keep this setting throughout
your LFS installation.</para>

<para>The LFS variable should of course be set to the mount point you
chose.</para>

<para>The LC_ALL variable controls the localization of certain programs,
making their messages follow the conventions of a specified country. If your
host system uses a version of <emphasis>glibc</emphasis> older than 2.2.4,
having LC_ALL set to something other than "C" or "POSIX" during this chapter
may cause trouble if you exit the chroot environment and wish to return later.
By setting LC_ALL to "POSIX" ("C" is an alias for "POSIX") we ensure that
everything will work as expected in the chroot environment.</para>

<para>LDFLAGS is a variable we set in order to prevent debugging symbols from
being compiled into our static packages. By omitting these symbols during
the linking stage of compilation, we save hard drive space and decrease our
build time.</para>

<para>We are now prepared to begin building the temporary tools which will
support us in later chapters.</para>

</sect1>