Is there a program to see channels used by Wi-Fi networks (similar to Vistumbler or inSSIDer) in Ubuntu?

In addition to Rozza's answer you can group the results and see how much each channel is used:

sudo iwlist wlan0 scan | grep Frequency | sort | uniq -c | sort -n

Example output would be like this (first column is count, see uniq -c ):

  1                     Frequency:2.422 GHz (Channel 3)
  1                     Frequency:2.432 GHz (Channel 5)
  1                     Frequency:5.26 GHz (Channel 52)
  1                     Frequency:5.5 GHz (Channel 100)
  2                     Frequency:2.452 GHz (Channel 9)
  2                     Frequency:2.472 GHz (Channel 13)
  3                     Frequency:2.447 GHz (Channel 8)
  6                     Frequency:2.437 GHz (Channel 6)
  6                     Frequency:2.462 GHz (Channel 11)
  7                     Frequency:5.18 GHz (Channel 36)
  8                     Frequency:2.412 GHz (Channel 1)

If you get something like wlan0 Interface doesn't support scanning, you have to replace wlan0 with the interface specified after running ifconfig (e.g. wlp2s0 etc).

Linssid

LinSSID is graphically and functionally similar to Inssider (Microsoft™ Windows®). It is written in C++ using Linux NL80211 tools, Qt5, and Qwt 6.1.

You can use this Linssid:

sudo apt install linssid

It will show you ssid, mac, power signal, and graphic.

I'm guessing you're looking to set to a channel that is not being used locally - so you want to see a summary of what is being used. Try the following from the command line:

sudo iwlist wlan0 scanning | grep -i Channel