CPU: 70
RAM: 45
HDD: 10

#!/bin/bash
echo CPU: `top -b -n1 | grep "Cpu(s)" | awk '{print $2 + $4}'`
FREE_DATA=`free -m | grep Mem`
CURRENT=`echo $FREE_DATA | cut -f3 -d' '`
TOTAL=`echo $FREE_DATA | cut -f2 -d' '`
echo RAM: $(echo "scale = 2; $CURRENT/$TOTAL*100" | bc)
echo HDD: `df -lh | awk '{if ($6 == "/") { print $5 }}' | head -1 | cut -d'%' -f1`

[root@dev ~]# df -lh
    Filesystem            Size  Used Avail Use% Mounted on
    /dev/mapper/vg_dev-lv_root
                           64G   31G   30G  51% /
    tmpfs                1004M  112K 1004M   1% /dev/shm
    /dev/sda1             485M   30M  430M   7% /boot


[root@dev ~]# top -b -n1
top - 13:39:49 up 8 days,  4:59,  3 users,  load average: 0.00, 0.01, 0.00
Tasks: 135 total,   1 running, 134 sleeping,   0 stopped,   0 zombie
Cpu(s):  1.2%us,  0.5%sy,  0.0%ni, 98.0%id,  0.3%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2055668k total,  1957592k used,    98076k free,   155640k buffers
Swap:  4128760k total,    83644k used,  4045116k free,   718168k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 1250 root      20   0 15028 1080  808 R  5.5  0.1   0:00.04 top
    1 root      20   0 19336 1176  976 S  0.0  0.1   0:01.80 init
    2 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kthreadd
    3 root      RT   0     0    0    0 S  0.0  0.0   0:00.00 migration/0
    4 root      20   0     0    0    0 S  0.0  0.0   0:00.00 ksoftirqd/0
    5 root      RT   0     0    0    0 S  0.0  0.0   0:00.00 watchdog/0
    6 root      20   0     0    0    0 S  0.0  0.0   0:00.15 events/0
    7 root      20   0     0    0    0 S  0.0  0.0   0:00.00 cpuset
    8 root      20   0     0    0    0 S  0.0  0.0   0:00.00 khelper
    9 root      20   0     0    0    0 S  0.0  0.0   0:00.00 netns
   10 root      20   0     0    0    0 S  0.0  0.0   0:00.00 async/mgr
   11 root      20   0     0    0    0 S  0.0  0.0   0:00.00 pm
   12 root      20   0     0    0    0 S  0.0  0.0   0:00.00 sync_supers
   13 root      20   0     0    0    0 S  0.0  0.0   0:00.00 bdi-default
   14 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kintegrityd/0
   15 root      20   0     0    0    0 S  0.0  0.0   0:00.45 kblockd/0
   16 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kacpid
   17 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kacpi_notify
   18 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kacpi_hotplug
   19 root      20   0     0    0    0 S  0.0  0.0   4:02.29 ata/0
   20 root      20   0     0    0    0 S  0.0  0.0   0:00.00 ata_aux
   21 root      20   0     0    0    0 S  0.0  0.0   0:00.00 ksuspend_usbd
   22 root      20   0     0    0    0 S  0.0  0.0   0:00.00 khubd
   23 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kseriod
   25 root      20   0     0    0    0 S  0.0  0.0   0:00.00 khungtaskd
   26 root      20   0     0    0    0 S  0.0  0.0   0:07.66 kswapd0
   27 root      25   5     0    0    0 S  0.0  0.0   0:00.00 ksmd
   28 root      39  19     0    0    0 S  0.0  0.0   0:06.30 khugepaged
   29 root      20   0     0    0    0 S  0.0  0.0   0:00.00 aio/0
   30 root      20   0     0    0    0 S  0.0  0.0   0:00.00 crypto/0