linux command line history

# history
presents you a list of historical command lines

# history n
lists the last n commands

# !546
executes(!) the command listed above at line 546

# !string
executes(!) the last command starting with string

to start a search in the history press "CTRL+r" and type your search string
(reverse-i-search)`': [string]
press "CTRL+r" again to search in result

remove linux kernels

sudo apt-get purge linux-image-x.x.x-x

freeees up space from /boot

reference: https://wiki.ubuntuusers.de/Skripte/Alte_Kernel_entfernen/

VBox mount shared folder from host

sudo mount -t vboxsf -o uid=$UID,gid=$(id -g) [name of shared folder from vbox-settings] [mount-shared-folder-to-path]

add user to group vboxsf:
usermod -a -G vboxsf [username]