Checking wifi signal stregnth in ubuntu

 Use command: watch -n1 iwconfig

Then check for "Link Quality"

Example Output:

br-162f0698aa15  no wireless extensions.

enp0s31f6  no wireless extensions.

lo        no wireless extensions.

veth7f181fd  no wireless extensions.

enx482ae3bc4b7c  no wireless extensions.

docker0   no wireless extensions.

wlp61s0   IEEE 802.11  ESSID:"******"
          Mode:Managed  Frequency:5.28 GHz  Access Point: **:**:**:**:**:**
          Bit Rate=866.7 Mb/s   Tx-Power=22 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=51/70  Signal level=-59 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:126   Missed beacon

Ubuntu: Convert multiple images to video

Use command: ffmpeg

 example:  

ffmpeg -framerate 10 -pattern_type glob -i '*.JPG'  output4.mp4

where  '*.JPG'  means it will take all files iwth extension JPG from current directory 

"-framerate 10" mean 10 images will be shown per second