3 examples for watch

  # run the free command (show amount of free memory) every one second.
watch -n1 free
        

  # watch changes in ifconfig live
watch ifconfig

#watch for mail, you might do

watch -n 60 from

#To watch the contents of a directory change, you could use

watch -d ls -l

#If you're only interested in files owned by user joe, you might use

watch -d 'ls -l | fgrep joe'

#To see the effects of quoting, try these out

watch echo $$
watch echo '$$'
watch echo "'"'$$'"'"

#To see the effect of precision time keeping, try adding -p to

watch -n 10 sleep 1

#You can watch for your administrator to install the latest kernel with

#watch uname -r
        

  # display active TCP connections
watch ss -at