Shell Programming and Scripting

root@:/>>vmstat 1 1

System configuration: lcpu=8 mem=20480MB

kthr    memory              page              faults        cpu    
----- ----------- ------------------------ ------------ -----------
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
 7  0 6205376  5184   0   0   0   0    0   0  30 92615 16469 95  5  0  0

#!/usr/bin/ksh

# set columns value into variable
set_val()
{
        unset vals # clear value array
        vals=($*)  # set values into array

        nflds=${#flds[*]}   # num of fields (headerline=columnnames)

        fld=0
        while ((fld<nflds))
        do
                varname=${flds[$fld]}    # colname
                eval $varname=\"\"       # set "" 1st, if it s not in this line
                eval $varname=\""${vals[$fld]}"\"    # set value fot variable
                ((fld+=1))
        done

}

# parse mem value
readmem()
{
        data="$*"
        lastf=${data##*=}   # last fld using delim =
        lastf=${lastf/MB/}   # remove MB
        echo "$lastf"
}


#MAIN
LANG=C    # desimal delimiter = .
header=0  # set 1 after columnnames has readed
data=0      # data started (--- ---- ---- ---- ...)
mem=0
# floating using 2 decimals
typeset -F2 mem1 mem2 mem


#testdata
echo "System configuration: lcpu=8 mem=20480MB

kthr    memory              page              faults        cpu
----- ----------- ------------------------ ------------ -----------
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
 7  0 6205376  5184   0   0   0   0    0   0  30 92615 16469 95  5  0  0" | while read line
do
        case "$line" in
                "System configuration:"*) mem=$(readmem "$line") && continue ;;
                "----"*) data=1 ; continue ;; # data start
        esac
        (( data == 0 )) && continue # no data yet
        (( header == 0 )) && flds=($line) && header=1 && continue # headerline
        set_val $line
        echo "avm:$avm"
        (( mem1=avm/256.00))
        (( mem2=mem1/mem*100.00 ))
        echo Mem:$mem Avm:$avm $mem1 $mem2  - (fre:$fre)
done