What is the difference between the -a and -o options when you use the Pear installer?

Question

When you use the Pear installer, like

pear install DB

you can use the '-a' option or the '-o' option.

What is the difference between them?

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@Ólafur Waage

I want to ask the difference between all and only.

I cannot understand what they are.

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What are the 'all' dependencies and what the 'only' dependencies?

Are there any differences between them?

My brain cannot distinguish them.

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OK, then, should I use the '-a' option?

Answer 1

I believe they are the short form of --alldeps and --onlyreqdeps

The PEAR installer has full support for dependencies; it can automatically install required and/or optional dependencies if you wish so.

Here's the PEAR Install command manual

EDIT:

What each does is in the manual, but here's the blurb.

You have several choices:

• Install dependent packages by hand

• Let PEAR automatically install necessary dependencies only

• Let PEAR automatically install necessary and optional dependencies

The first method can be a painful and daunting process, because dependent packages itself can have dependencies.

Both other methods just require a switch to the install command, either --onlyreqdeps (install required dependencies only) or --alldeps (install all dependencies).