Learning about actual memory usage

ps -ao comm,size,rss,vsize
COMMAND            SZ   RSS    VSZ
zsh               532  1504   5556
geany           14320 17136  47980
zsh               552  1612   5576
geany           12832 15316  46140
ruby            11536 12080  17600
sleep             292   492   4012
ps                636   772   4484

Learning about the libraries

ldd firefox-bin 
        linux-gate.so.1 =>  (0xffffe000)
        libpthread.so.0 => /lib/i686/libpthread.so.0 (0xb786c000)
        libxul.so => not found
        libxpcom.so => not found
        libmozalloc.so => not found
        libplds4.so => /lib/libplds4.so (0xb7866000)
        libplc4.so => /lib/libplc4.so (0xb7860000)
        libnspr4.so => /lib/libnspr4.so (0xb7823000)
        libdl.so.2 => /lib/libdl.so.2 (0xb781e000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7735000)
        libm.so.6 => /lib/i686/libm.so.6 (0xb770a000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0xb76ec000)
        libc.so.6 => /lib/i686/libc.so.6 (0xb756e000)
        /lib/ld-linux.so.2 (0xb7897000)

Counting the number of libraries

ldd firefox-bin | wc -l
14