Site Backup in MOSS 2007

To take the backup in moss 2007 in command promp

stsadm.exe is in the following installation path
"C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN\stsadm.exe"


Syntax :
stsadm.exe -o backup -url -filename

Example :
stsadm.exe -o backup -url http://localhost:2100 -filename backup.dat

if you want to overwrite the existing backup file use -overwrite with the command
stsadm.exe -o backup -url http://localhost:2100 -filename backup.dat -overwrite

It will take all subsites in given web application URL.