# ==[ Compound commands: pipelines
#
# A compound command consists of multiple commands arranged together in
# some grouping, such as pipeline, a loop, a conditional statement, etc.
# Reserved words are used to delimit compound commands, although there are
# some exceptions.
#
# Pipelines
#
# A pipeline is a sequence of one or more commands separated by | or |&.
# The output of each command in the pipeline is connected via a pipe to the
# input of the next command.
# By using |&, stderr and stdout are connected to stdin of the next
# command.
# Each command in the pipeline is executed in its own subshell, which is a
# separate process (more about this later).
# The exit status of a pipeline is the exit status of the last command in
# the pipeline (this can be changed with a shell option).
# The shell waits for all commands in the pipeline to finish if the
# pipeline is executed asynchronously.
#
# Example: echo "one two" | rev
# 
# Example: echo "one two" | cut -f' ' -d2 | rev