brew install pv

source ./demorunner.sh sample_commands.txt

source ./demorunner.sh sample_commands.txt 2

$ demorunner.sh

This utility enables the simulation of 'live typing' for command-line driven demos by echoing and executing
a list of commands that you provide in a 'commands file'.

Usage:
source ./demorunner.sh (commands-file) [start-with-line-number]

Command-line arguments:
  commands-file           - Name of the file with the list of commands to execute. Required.
  start-with-line-number  - Line number in the commands file at which to begin execution. Optional. Default is 1.
                            #_ECHO_ON & #_ECHO_OFF commands above the starting line will still be respected, but
                            other lines will be ignored.

The following flags can be used in the commands file:
  #_ECHO_ON   - Turns on echoing and execution of subsequent commands. Must be placed in its own line.
                When #_ECHO_ON is enabled, user must press the Return key once to echo the next command, and again
                to execute it. This is the default mode.
  #_ECHO_OFF  - Turns off echoing of subsequent commands. Commands will be executed immediately, without user input.
                Must be placed in its own line.
  #_ECHO_#    - Strips tag and echoes command starting from #. Must be placed at the beginning of the line.

Otherwise, lines starting with # will be ignored.

The following environment variables can be used to modify the behavior of the script:
  DEMO_COLOR  - May be yellow, blue, or white. Default is yellow.
  DEMO_DELAY  - Controls the rate of the echoing of commands to simulate live typing. Default is 10.
                Set to 0 to disable rate-limiting. Increase the setting to make typing appear faster.

During execution of your commands file, you may also type a custom command at any time. Once your custom command is
executed, press Return at the next empty prompt to continue with the next command from the commands file.

--- Known issues/To-do List:

- Up/Down/Left/Right arrows have no effect.
- Tab/autocompletion does not work.