Getting GDB to save a list of breakpoints

As of GDB 7.2 (2011-08-23) you can now use the save breakpoints command.

save breakpoints <filename>
  Save all current breakpoint definitions to a file suitable for use
  in a later debugging session.  To read the saved breakpoint
  definitions, use the `source' command.

Use source <filename> to restore the saved breakpoints from the file.

This answer is outdated. GDB now supports saving directly. See this answer.

You can use logging:

(gdb) b main
Breakpoint 1 at 0x8049329
(gdb) info break
Num     Type           Disp Enb Address    What
1       breakpoint     keep y   0x08049329 <main+16>
(gdb) set logging file breaks.txt
(gdb) set logging on
Copying output to breaks.txt.
(gdb) info break
Num     Type           Disp Enb Address    What
1       breakpoint     keep y   0x08049329 <main+16>
(gdb) q

The file breaks.txt now contains:

Num     Type           Disp Enb Address    What
1       breakpoint     keep y   0x08049329 <main+16>

Writing an AWK script that transforms that into a format useful for the .gdbinit or a --command file is easy. Or you may even make the script emit separate --eval-command's to the GDB command line...

Adding this small macro to .gdbinit will help you do it:

# Call with dump_breaks file.txt
define dump_breaks
    set logging file $arg0
    set logging redirect on
    set logging on
    info breakpoints
    set logging off
    set logging redirect off
end

Put your GDB commands and breakpoints in a .gdbinit file just as you might type them at the gdb> prompt, and GDB will automatically load and run them on startup. This is a per-directory file, so you can have different files for different projects.

An extension to anon's extension to Johannes' answer:

.gdbinit:

define bsave
    shell rm -f brestore.txt
    set logging file brestore.txt
    set logging on
    info break
    set logging off
    # Reformat on-the-fly to a valid GDB command file
    shell perl -n -e 'print "break $1\n" if /^\d+.+?(\S+)$/g' brestore.txt > brestore.gdb
end
document bsave
  store actual breakpoints
end

define brestore
  source brestore.gdb
end
document brestore
  restore breakpoints saved by bsave
end

With brestore you can then restore the breakpoints saved with bsave.