echo `/bin/ipcalc --silent --hostname $(/sbin/ifconfig eth0 | sed -n -e "s/^.*addr://g" -n -e "s/ Bcast.*//p")` To put in a file from the command line: echo `/bin/ipcalc --silent --hostname $(/sbin/ifconfig eth0 | sed -n -e "s/^.*addr://g" -n -e "s/ Bcast.*//p")` >> test