readline package has been compiled in, then when
units is used interactively, numerous command line editing
features are available. To check if your version of
readline, invoke the program with the
For complete information about
readline, consult the
documentation for the
readline package. Without any
units will allow editing in the style of
emacs. Of particular use with
units are the completion
If you type a few characters and then hit ESC followed by
units will display a list of all the units that
start with the characters typed. For example, if you type metr and
then request completion, you will see something like this:
You have: metr metre metriccup metrichorsepower metrictenth metretes metricfifth metricounce metricton metriccarat metricgrain metricquart metricyarncount You have: metr
If there is a unique way to complete a unitname, you can hit the TAB key
units will provide the rest of the unit name. If
beeps, it means that there is no unique completion. Pressing the TAB
key a second time will print the list of all completions.
The readline library also keeps a history of the values you enter.
You can move through this history using the up and down arrows. The
history is saved to the file .units_history in your home
directory so that it will persist across multiple
invocations. If you wish to keep work for a certain project separate
you can change the history filename using the --history
option. You could, for example, make an alias for
units --history .units_history so that
save separate history in the current directory.
The length of each history file is limited to 5000 lines. Note also that if
you run several concurrent copies of
units each one will save
its new history to the history file upon exit.