linux-hints

I'm fed up looking up Linux set up instructions on the internet... Time to make my own reference.

Image stuff

Change screenshot default folder

$ gsettings set org.gnome.gnome-screenshot auto-save-directory "[complete-path-to-new-directory]"

Fix PDF thumbnails

$ sudo vim /etc/apparmor.d/local/usr.bin.evince

then add to end of file

owner /tmp/{,.}gnome-desktop-thumbnailer.* w,

finally rm -rf ~/.cache/thumbnails/ for good measure and reboot.

Name adjustments

Change username, groupname, and ~$ dir

First kill everything (ideally you'd do this from a different user or superuser account)

$ sudo pkill -u [old-username]
$ sudo pkill -9 -u [old-username]
$ sudo usermod -l [new-username] [old-username]

Change the Home directory name

$ sudo usermode -d /home/[new-username] -m [new-username]

Change the groupname

$ sudo groupmod -n [new-username] [old-username]

Change hostname

$ sudo hostnamectl set-hostname [new-hostname]

Memory adjustments

Clear cache

As superuser (sudo won't work, need to do su or on Ubuntu sudo -i then type that):

# echo 1 > /proc/sys/vm/drop_caches

See and adjust swappiness

$ cat /proc/sys/vm/swappiness
$ sysctl vm.swappiness=[0-100, most recommend 10 (default is 60)]

See and adjust inode cache

$ cat /proc/sys/vm/vfs_cache_pressure
$ sysctl vm.vfs_cache_pressure=50 (default is 100)

Do both of the above permanently

Using your favorite text editor (in my case vim)

$ sudo vim /etc/sysctl.conf

at the bottom add the following lines:

vm.swappiness=10
vm.vfs_cache_pressure=50

then run this line:

$ sudo sysctl -p

GPU

Fix for not waking up after suspend (monitor black but computer running): /usr/bin/nvidia-sleep.sh needs to be disabled by setting exit 0 at the top of the file.

Versions

OS version + Ubuntu version for Ubuntu based systems:

$ cat /etc/os-release

Debian version in Ubuntu based systems:

$ cat /etc/debian_version

392781/linux-hints