hdiutil convert /path/to/filename.iso -format UDRW -o /path/to/savefile.dmg

hdiutil convert /path/to/filename.dmg -format UDTO -o /path/to/savefile.iso

top -l 1| awk '/CPU usage/ {print "CPU: " $8, $9, $10, $11, $12, $13}'
top -l 1 | awk '/PhysMem/ {print "RAM: used: " $8 " free: " $10}'
uptime | awk '{sub(":", "h ", $3); sub(",", "min", $3); print "Time since last system boot: " $3}'

system_profiler SPHardwareDataType SPSoftwareDataType | perl -e '@info= ; $info= join("", @info);if($info=~m@[\r\n]+\s*Computer Name:\s*([^\r\n]+)[\r\n]+@) {print "$1\n";}if($info=~m@[\r\n]+\s*System Version:\s*([^\r\n]+)[\r\n]+@) {print "$1\n";}if($info=~m@[\r\n]+\s*Memory:\s*([^\r\n]+)[\r\n]+@) {print "$1\n";}if($info=~m@[\r\n]+\s*Total Number Of Cores:\s*([^\r\n]+)[\r\n]+@) {print "$1 x ";}if($info=~m@[\r\n]+\s*Processor Speed:\s*([^\r\n]+)[\r\n]+@) {print "$1 ";}if($info=~m@[\r\n]+\s*Processor Name:\s*([^\r\n]+)[\r\n]+@) {print "$1\n";}'

#! /bin/bash
myen0=`ifconfig en0 | grep "inet " | grep -v 127.0.0.1 | awk '{print $2}'`
if [ "$myen0" != "" ]
then
    echo "Ethernet : $myen0"
else
    echo "Ethernet : INACTIVE"
fi
myen1=`ifconfig en1 | grep "inet " | grep -v 127.0.0.1 | awk '{print $2}'`
if [ "myen1" != "" ]
then
    echo "AirPort  : $myen1"
else
    echo "Airport  : INACTIVE"
fi
echo External : `curl -s http://checkip.dyndns.org/ | sed 's/[a-zA-Z/ :]//g'`

#!/bin/sh
# created by chris helming.
# chris dot helming at gmail
# get the current number of bytes in and bytes out
myvar1=`netstat -ib | grep -e "en1" -m 1 | awk '{print $7}'` #  bytes in
myvar3=`netstat -ib | grep -e "en1" -m 1 | awk '{print $10}'` # bytes out
#wait one second
sleep 1
# get the number of bytes in and out one second later
myvar2=`netstat -ib | grep -e "en1" -m 1 | awk '{print $7}'` # bytes in again
myvar4=`netstat -ib | grep -e "en1" -m 1 | awk '{print $10}'` # bytes out again
# find the difference between bytes in and out during that one second
subin=$(($myvar2 - $myvar1))
subout=$(($myvar4 - $myvar3))
# convert bytes to kilobytes
kbin=`echo "scale=2; $subin/1024;" | bc`
kbout=`echo "scale=2; $subout/1024;" | bc`
# print the results
echo "IN : $kbin Kb/sec"
echo "OUT: $kbout Kb/sec"