Useful Commands

lsb_release  -a
Displays current OS release.
sudo  apt  update
Fetches list of current software versions.
sudo  apt  upgrade
Installs updated versions.
upower  -d
Displays battery status.
showmount  -e hostname
Shows remote filesystems exported by the other host.
find  .  -type f  |  tr  '\n'  '\0'  |  xargs  -0  ls -lt
Lists files, sorted by change date, handling special characters in names.
convert  -resize 50%  .Images/input.png  .Images/output.jpeg
Resizes images. (Note dangerous syntax.)
arecord  --channels=2  output.wav
Record sound from microphones.
exiftime  -f  -ta  -v+26d  -w  20171227_*.jpeg
Sets date and time on image.
fuser -c /media/ray/xxx
Shows which processes are keeping mount busy.
sudo lshw -html >hardware.html
Shows hardware configuration.
openssl s_client -connect mailservices.uwaterloo.ca:993
Detect unread mail.
        openssl s_client -connect mailservices.uwaterloo.ca:993
        1 login rbutterw <password>
        2 select inbox
        3 search unseen
        * SEARCH 11 13 14 16
        3 OK Completed (4 msgs in 0.000 secs)
        4 logout
deja-dup
^H - shows hidden dotfiles
^L - allows typing location
screenshot
print
Take a Screenshot
Alt+Print
Take a Screenshot of window
Shift+Print
Take a Screenshot of an area
Ctrl+Print
Copy a Screenshot to the clipboard
Ctrl+Alt+Print
Copy a Screenshot of a window to the clipboard
Shift+Alt+Print
Copy a Screenshot of an area to the clipboard