NAME

patra - Play back shell commands for live demonstrations

SYNOPSIS

patra [-m] COMMAND_FILE

DESCRIPTION

Important: patra is an experimental fork from cleo. You should check the current differences from App-Cleo and decide, which one you want to use. It may be, that in your current time, patra is merged back into cleo or obsolete for other reasons.

patra is a utility for playing back pre-recorded shell commands in a live demonstration. patra displays the commands as if you had actually typed them and then executes them interactively.

There is probably an easy way to do this with expect or a similar tool. But I couldn't figure it out, so I built this. Your mileage may vary.

PLAYBACK

patra pauses and waits for a keypress before displaying a command and before executing it. Pressing any key besides those listed below will advance the playback:

Key                       Action
------------------------------------------------------------------
s                         skip the current command
r                         redo the current command
p                         redo the previous command
c                         run all remaining commands
q                         quit playback
[number][not a digit]     jump to specific command number

COMMANDS

patra reads commands from a file. Each line is treated as one command. Blank lines and those starting with # will be ignored. The commands themselves can be anything that you would type into an interactive shell. You can also add a few special tokens that patra recognizes:

!!!

Commands starting with !!! (three exclamation points) are not displayed and will be executed immediately. This is useful for running setup commands at the beginning of your demonstration.

...

Commands starting with ... (three periods) will be executed without waiting for a keypress. This is useful if you want to show a series of commands but don't need to stop and explain each one as you go.

%%%

Within a command, %%% (three percent signs) will cause playback to pause and wait for a keypress before displaying the rest of the command. This is useful if you want to stop in the middle of a command to give some explanation.

$

This syntax is only supported, when you start patra with the option -m. You then should preceed each commend with $ (Dollar, Space). Your advantage then is, that you can scatter your commands over mutliple lines, as far as Bash can handle it.

Otherwise, patra displays and executes the commands verbatim. Note that some interactive commands like vim are picky about STDOUT and STDIN. To make them work properly with patra, you may need to force them to attach to the terminal like this:

(exec < /dev/tty vim)

EXAMPLE

Ryan uses this for giving demonstrations of pinto, such as the one seen at https://www.youtube.com/watch?v=H-JkFXm8Xgk (the live demonstration part starts around 10:47).

The command file that I use for that presentation is included inside this distribution at examples/pinto.demo. This file is for illustration only, so don't expect it to actually work for you.

LIMITATIONS

patra only works on Unix-like platforms.

TODO

Support backspacing in recorded command

Write unit tests

AUTHOR

Jeffrey Ryan Thalhammer <thaljef@cpan.org>

Boris Däppeb (BORISD) <bdaeppen.perl@gmail.com>

COPYRIGHT

cleo - Copyright (c) 2014, Imaginative Software Systems

patra - Boris Däppen (BORISD) 2018