From: "nobu (Nobuyoshi Nakada) via ruby-core" <ruby-core@...>
Date: 2026-04-02T13:22:59+00:00
Subject: [ruby-core:125182] [Ruby Feature#21976] Add $SECONDS, $RANDOM, and other bashisms

Issue #21976 has been updated by nobu (Nobuyoshi Nakada).


Sorry to be late: https://github.com/nobu/bashism

----------------------------------------
Feature #21976: Add $SECONDS, $RANDOM, and other bashisms
https://bugs.ruby-lang.org/issues/21976#change-116916

* Author: jhawthorn (John Hawthorn)
* Status: Open
----------------------------------------
Some time ago there was a lot of discussion around a script named [safe_sleep.sh](https://github.com/actions/runner/blob/af6c8e6eddef233fdef862c1287d9b013c8aabff/src/Misc/layoutroot/safe_sleep.sh) in the GitHub Actions runner. Like [many others](https://github.com/actions/runner/issues/2380), I immediately saw the serious problem with this script: it isn't written in Ruby!

To better support this use case, and to be able to sleep safely, Ruby should support `$SECONDS` as well as other bashisms like `$RANDOM`, `$1`, etc.

This would allow us to rewrite

```bash
#!/bin/bash

SECONDS=0
while [[ $SECONDS != $1 ]]; do
    :
done
```

In Ruby


```ruby
#!/usr/bin/env -S ruby -rbashisms
$SECONDS = 0
while $SECONDS != $1.to_i
    ;
end
```

```
$ ruby -rbashisms -e 'echo $BASH_VERSION'
4.1.2026(4.0.1)-release (ruby)
$ ./safe_sleep.rb 5

```

For ease of evaluating this proposed feature I've have created the [`bashisms` gem](https://github.com/jhawthorn/bashisms) please give it a try!



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