Linux From Scratch
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# About debugging symbols

Most programs and libraries by default are compiled with debugging symbols and optimizing level 2 (gcc options -g and -O2) and are compiled for a specific CPU. On Intel platforms software is compiled for i386 processors by default. If you don't wish to run software on other machines other than your own, you might want to change the default compiler options so that they will be compiled with a higher optimization level, no debugging symbols and generate code for your specific architecture. Let me first explain what debugging symbols are.

A program compiled with debugging symbols means you can run a program or library through a debugger and the debugger's output will be user friendlier. These debugging symbols also enlarge the program or library significantly.

To remove debugging symbols from a binary (must be an a.out or ELF binary) run `strip --strip-debug filename` You can use wild cards if you need to strip debugging symbols from multiple files (use something like strip --strip-debug $LFS/usr/bin/*). Another, easier, options is just not to compile programs with debugging symbols. Most people will probably never use a debugger on software, so by leaving those symbols out you can save a lot of diskspace.

Before you wonder if these debugging symbols would make a big difference, here are some statistics:

- A dynamic Bash binary with debugging symbols: 1.2MB

- A dynamic Bash binary without debugging symbols: 478KB

- /lib and /usr/lib (glibc and gcc files) with debugging symbols: 87MB

- /lib and /usr/lib (glibc and gcc files) without debugging symbols: 16MB

Sizes may vary depending on which compiler was used and which C library version was used to link dynamic programs against, but your results will be similar if you compare programs with and without debugging symbols. After I was done with this chapter and stripped all debugging symbols from all LFS binaries and libraries I regained a little over 102 MB of disk space. Quite the difference.

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