…olas-grekas)

This PR was merged into the 4.4 branch.

Discussion
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[Process] change the syntax of portable command lines

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #34838
| License       | MIT
| Doc PR        | symfony/symfony-docs#12772

An alternative to #34845

Right now, portable command lines use `"$FOO"` for placeholders.
But because we validate that a corresponding variable exists before running the command, this fails with `Command line is missing a value for key "$FOO"` when `FOO` is not defined.

This PR proposes to use `"${:FOO}"` instead. The difference with the previous syntax is that this cannot collide with existing shell scripts as it is invalid for them.

When this is merged, we'll have to update https://symfony.com/blog/new-in-symfony-4-1-prepared-commands too.

Commits
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3c7b775 [Process] change the syntax of portable prepared command lines

…rekas)

This PR was merged into the 4.4 branch.

Discussion
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Update paragraph about portable command lines

Follows symfony/symfony#34848

Commits
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35556da Update paragraph about portable command lines

This PR was merged into the 5.2 branch.

Discussion
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[Process] Remove paragraph from bad merge

This paragraph was removed in #12772, yet it's still in the 5.2 branch. (and it's wrong)

Commits
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5ca0b24 [Process] Remove paragraph from bad merge