How can I boot into the recovery from terminal? I'm using LG p970/CM10/cwm5
It may not work if you have not-always-compatibile busybox reboot symlink in a PATH that is more privileged than /system/bin (or /system/bin toolbox symlink has been overwritten), it may lie in /sbin if using custom kernel with bb included for example. If so, try: "toolbox reboot recovery" (jb) "/system/bin/reboot recovery" (kk - however which one will work my be also dependent from the manufacturer...)
If you are running CM11 or CM12 you can simply go to Settings> About Phone> and tap Build Number 7-10 times to unlock Dev Options. Once unlocked you can go to Setting > Developer Options and select Advanced Reboot, this will add a "Reboot to Recovery" option to your reboot menu. Easiest method I have found to get unto recovery without installing a 3rd party app or using a terminal command if your phone doesn't want to accept a multi button sequence. Also note that in Cyanogenmod 12 you have to enable the Superuser root access in the Dev options first I believe.