I currently have a statistics gathering script i run on my Linux servers. One of the stat i gather is total memory in the machine. The script is all perl with the exception of gathering the memory for that i use the following command:

 $ram = (`cat /proc/meminfo |  grep "MemTotal" | awk '{print \$2}'`);

Check the Linux::MemInfo module at cpan:

$ 
$ cat /proc/meminfo |  grep "MemTotal" | awk '{print $2}'
961528
$ 
$ perl -le 'BEGIN{use Linux::MemInfo} %mem=get_mem_info; print $mem{"MemTotal"}'
961528
$ 
$