From Bash Reference Manual

A pipeline is a sequence of simple commands separated by one of the control operators | or |&.

From POSIX 2013

A pipeline is a sequence of one or more commands separated by the control operator |.

I know that Bash has many extensions to POSIX shells, e.g. |&.

But are the component commands of a pipeline

• simple commands or
• just any commands (simple, pipeline again, list, compound, and function)?

In Bash, the following works

$ for f in ls *; do echo $f; done | cat

but the first component command of the pipeline isn't simple but compound.

From Bash Reference Manual

A pipeline is a sequence of simple commands separated by one of the control operators | or |&.

From POSIX 2013

A pipeline is a sequence of one or more commands separated by the control operator |.

I know that Bash has many extensions to POSIX shells, e.g. |&.

But are the component commands of a pipeline

• simple commands or
• just any commands (simple, pipeline again, list, compound, and function)?

In Bash, the following works

$ for f in $(ls *); do echo $f; done | cat

but the first component command of the pipeline isn't simple but compound.

From Bash Reference Manual

A pipeline is a sequence of simple commands separated by one of the control operators | or |&.

From POSIX 2013

A pipeline is a sequence of one or more commands separated by the control operator |.

I know that Bash has many extensions to POSIX shells, e.g. |&.

But are the component commands of a pipeline

• simple commands or
• just any commands (simple, pipeline again, list, compound, and function)?

From Bash Reference Manual

A pipeline is a sequence of simple commands separated by one of the control operators | or |&.

From POSIX 2013

A pipeline is a sequence of one or more commands separated by the control operator |.

I know that Bash has many extensions to POSIX shells, e.g. |&.

But are the component commands of a pipeline

• simple commands or
• just any commands (simple, pipeline again, list, compound, and function)?

In Bash, the following works

$ for f in ls *; do echo $f; done | cat

but the first component command of the pipeline isn't simple but compound.