watch - execute a program periodically

showing output fullscreen

not available on El Captian OS

watch [-dhvt] [-n seconds] [--differences[=cumulative]] [--help] [--interval=seconds] [--no-title] [--version] command

runs command repeatedly, displaying its output (the first screenfull). allowing watching the output change over time.

--interval seconds
interval between executions of command
Default, 2.0 seconds, i.e. fraction seconds is allowed.
highlight the differences between successive updates.

=cumulative highlighting "sticky", presenting a running display of all positions that have ever changed.

turns off the header showing the interval, command, and current time at the top of the display, as well as the following blank line.
Runs until interrupted by signal intr usually ^c and
then it clears the screeen.

The command is given to sh -c may need to use extra quoting

POSIX option processing is used (i.e., option processing stops at the first non-option argument).
ie: flags after command don't get interpreted by watch


Watch changes is disk usage on various volumes
watch -d=c /bin/df
Watch significant changes is disk usage on various volumes by displaying sizes in megabytes!
watch -d=c /bin/df


Watch does not notice if the terminal window is resized and will produce poor "title" display if windows is resized.