testing.md

demosh -- demo shell

demosh can display Markdown while also running code contained in bash or sh blocks in the Markdown file.

When running this Markdown file with demosh, we start out not displaying things, because we haven't seen a SHOW directive yet. So this block will be readable in the Markdown file, but it won't be shown when feeding this file to demosh.

This is a header, but it won't be shown when running the demo.

clear
echo "This will run like a normal script."

The bash above will run even though we're still not showing anything yet.

We can import things from other files. Note that directives to demosh need to either be in Markdown comments, or in bash blocks. We'll use a Markdown comment here.

We can define hooks too.

#@hook nonexistant NONEXISTANT

The @SHOW and @HIDE directives control whether we're showing commands, waiting for the user to confirm proceeding, etc., or just reading through things non-interactively. The @SHOW directive below (in a comment, so you won't see it in the Markdown preview) tells demosh to start doing its thing.

Welcome to our demo!

Since these are headers, demosh will colorize them.

Kind of, anyway. It's kind of a best-effort sort of thing.

Here's some more Markdown. Underscores are highlighted. So are backticks and asterisks and doubled asterisks. But, also, e.g. 5 * 4 == 20. How about 4 or 44 45 46?

How about hello world for emphasis?

• Asterisks can also be list items.

• So can dashes.

Backticks don't do other formatting, so COLOR_NAME should format correctly, as should _*_*_*_*_.

You can also use the @print directive to produce colorized output:

#@print This will be ordinary black text.
#@print # This will be red like a comment.

The @ifhook directive

First let's check for hooks. If you've set $DEMO_HOOK_BROWSER to a nonempty value, you should see "we have a browser hook!" here.

#@ifhook show_browser
#@immed
echo "We have a browser hook!"
#@endif

As long as you haven't set $DEMO_HOOK_NONEXISTANT to a nonempty value, you should not see "we have a nonexistant hook?" here.

#@ifhook nonexistant
#@immed
echo 'We have a nonexistant hook?'
#@endif

Hit RETURN to continue (this is the wait directive).

Assignments and functions

Let's try an assignment.

FOO="Hello world"
echo "$FOO"

exported assignments work too. (The word export itself is a noop in demosh, to be clear: variables are always exported.)

export BAR="Exported hello world"
echo "$BAR"

The $SHELL environment variable should be overwritten to be demosh itself.

echo "SHELL is $SHELL"

Here's a function definition with the function keyword...

function hello() {
    echo "Hello, $1!"
}

...and here's one without it.

hello2 () {
    echo "Hello again, $1!"
}

Can we run the functions?

hello "world"
hello2 "world"

Assignments persist across blocks, of course.

echo $FOO
echo $BAR

cd

cd is handled internally, because it has to be.

cd /tmp
pwd

Macros

Let's test macro calls. While we're at it, let's show that we can have comments in bash blocks too.

wait_clear

# How about an immediate macro call?
#@wait_then_date

Waiting (or not)

Here, we'll need to hit RETURN to run our command.

echo "Waiting only before"

This is an immediate command: no waiting at all.

#@immed
echo "No waiting."

Here we wait before and after.

#@waitafter
echo "Waiting before and after"

#@waitafter
#@nowaitbefore
echo "Waiting only after"

Let's try the function again.

hello "world again"

Signal Handling

Let's test signal handling. You should be able to hit Ctrl-C to interrupt the sleep.

sleep 120

And that's the whole demosh Markdown demo!!