You can find the memory used by a program (process) by looking into /proc directory or using standard command such as ps or top.

However, you must calculate all memory usage by hand i.e. add Shared Memory + mapped file + total virtual memory size of the process + Resident Set Size + non-swapped physical memory used by process. So how do you find the total memory used by a process or program under Linux? Use a tool called pmap. It reports the memory map of a process or processes.

$ pmap pid

$ pmap 3724

If you want to see the exented format
The -x option can be used to provide information about the memory allocation and mapping types per mapping. The amount of resident, non-shared anonymous, and locked memory is shown for each mapping:

$ pmap -x 3526

$ pmap -d 3526

$ pmap -q 3526

-x extended Show the extended format.

-d device Show the device format.

-q quiet Do not display some header/footer lines.

-V show version Displays version of program.