6.72. Stripping Again

If the intended user is not a programmer and does not plan to do any debugging on the system software, the system size can be decreased by about 90 MB by removing the debugging symbols from binaries and libraries. This causes no inconvenience other than not being able to debug the software fully anymore.

Most people who use the command mentioned below do not experience any difficulties. However, it is easy to make a typo and render the new system unusable, so before running the strip command, it is a good idea to make a backup of the LFS system in its current state.

First back up some libraries who's debug symbols are needed when running regression tests in BLFS packages:

save_libs="ld- libatomic libc- libcilkrts libitm libmpx libpthread"
save_libs="$save_libs libquadmath libsanitizer libstdc++ libthread_db libvtv"

mkdir -p /var/dbg/lib /var/dbg/usr/lib

for lib in $save_libs
do
    find /usr/lib -name ${lib}*so* -type f -exec cp {} /var/dbg/usr/lib \;
    find /lib     -name ${lib}*so* -type f -exec cp {} /var/dbg/lib     \;
done

Before performing the stripping, take special care to ensure that none of the binaries that are about to be stripped are running. If unsure whether the user entered chroot with the command given in Section 6.4, “Entering the Chroot Environment,” first exit from chroot:

logout

Then reenter it with:

chroot $LFS /tools/bin/env -i            \
    HOME=/root TERM=$TERM PS1='\u:\w\$ ' \
    PATH=/bin:/usr/bin:/sbin:/usr/sbin   \
    /tools/bin/bash --login

Now the binaries and libraries can be safely stripped:

/tools/bin/find /usr/lib -type f -name \*.a \
   -exec /tools/bin/strip --strip-debug {} ';'

/tools/bin/find /lib /usr/lib -type f -name \*.so* \
   -exec /tools/bin/strip --strip-unneeded {} ';'

/tools/bin/find /{bin,sbin} /usr/{bin,sbin,libexec} -type f \
    -exec /tools/bin/strip --strip-all {} ';'

A large number of files will be reported as having their file format not recognized. These warnings can be safely ignored. These warnings indicate that those files are scripts instead of binaries.

If desired, restore the saved libraries with the debug data intact. The files can restored now or just held for later use. Note that several of the files cannot be copied directly after rebooting to the new LFS system. Later use requires booting to another system, mounting the LFS partition, and then copying the files.

cp -av /var/dbg/lib/* /lib
cp -av /var/dbg/usr/lib/* /usr/lib