bt command

Last updated on Jul 3, 2021

The bt command enqueues a command to be executed at the next system reboot using the boot time interface of UltraDefrag. Also the bt command can reboot the computer to proceed with the boot time defragmentation immediately:

C:\Program Files\UltraDefrag>bt udefrag c:

Boot time defragmentation requires a system reboot.
R - Reboot now, L - Reboot later, C - Cancel [R,L,C]?

If the command to be enqueued is the udefrag command (as in the example above) the bt command sets all the boot time environment variables accordingly to the currently set environment variables. If the command to be enqueued is the call command, however, the bt command does not set the environment variables before the call, for the sake of easier maintenance of the custom boot time scripts.

The bt command is part of the UltraDefrag Supplementary Scripts. Download the scripts and put them to the installation directory of UltraDefrag to be able to use the command.


bt [options] <command> [arguments]


By default the bt command displays a confirmation before enqueuing the specified command. You can skip the confirmation, however, using the following options:

/EEnqueue the command without asking for confirmation.
/REnqueue the command and reboot the computer, without asking for confirmation.


As the bt command is a batch script, you have to use the system call command to call it from your batch scripts:

call "%UD_INSTALL_DIR%\bt.cmd" /E udefrag c: